Dinosaur bones, royal jewels and ultra-rare Pokémon cards? They're just a taste of the outrageously expensive collectibles the world's multimillionaires and billionaires are coveting right now.

The new status symbols for those who have everything, the most sought-after are highly lucrative investments to boot. Read on to discover what the mega-wealthy are currently blowing their fortunes on, with insights from the 2025 Knight Frank Luxury Report. All dollar amounts in US dollars.

The 2025 Knight Frank Luxury Report offers a fascinating glimpse into the extravagant lifestyles of the world's richest people.

Contained within the report, the Knight Frank Luxury Investment Index (KFLII) tracks 10 collectible categories. As investments, they have outperformed the S&P 500 over the past two decades. But amid a relatively muted market, five categories saw price drops in 2024, with art – the worst performer – down by over 18%. And the five that appreciated did so only modestly: the best, handbags, grew in price by just 2.8%

Yet certain items within the 10 categories are in sizzlingly hot demand among the planet's ultra-high-net-worth individuals (UHNWIs), from the aforementioned dinosaur bones to Miami Vice Lamborghinis, Banksy paintings and Hermès Birkin bags. These super-exclusive must-haves are surging in value – and selling for astronomical sums.

Let's break them down, starting with the fossils...

Dinosaur bones are the latest billionaire trophy buy. Bragging rights are guaranteed with these uber-exclusive collectibles, which even many UHNWIs, who are defined as having a net worth of $30 million (£23.3m) or more, struggle to afford.

Last July, a 150 million-year-old stegosaurus nicknamed Apex sold at Sotheby's New York for a record-breaking $44.6 million (£34.6m). The buyer? Billionaire hedge-fund supremo Ken Griffin, who promptly loaned the prized fossil to the American Museum of Natural History in New York.

When it comes to fine jewellery, not just any old Cartier or Chopard will do for the world's most moneyed people. Now, the bling has to have a royal connection to have any real clout.

In November 2024, a diamond necklace (pictured) linked to ill-fated queen Marie Antoinette and a scandal that helped bring down the French monarchy fetched $4.8 million (£3.1m) at a Sotheby's sale in Geneva. Other recent auctions of royal jewels include a sale of 100 exquisite pieces from the collection of Tsar Ferdinand of Bulgaria.

Boasting about owning a standard Ferrari won't impress a billionaire. But a 1960 250 GT SWB California Spyder? That's sure to get their attention. For the mega-rich, the rarer the car, the better, and this beauty certainly fits the bill given only 56 were produced.

The very first, considered the finest of the bunch, changed hands at an RM Sotheby's Monterey sale last August for more than $17 million (£13.2m).

Brash 1980s and 1990s sportscars are all the rage right now among younger buyers, with the Lamborghini Countach LP5000 QV the go-to for many, according to Knight Frank. The slick vehicle starred in the stylish classic crime series Miami Vice and just screams 1980s luxe.

The head-turner is absolutely smashing it as an investment, having appreciated by a massive 60% over the past five years. This is all the more impressive since collectible cars overall have risen by only half that figure during the same period. A 1988 model in good condition now sells for an average of $605,000 (£470k), as per automotive lifestyle and insurance company Hagerty.

The flushest buyers have also developed a penchant for more discreet, performance-focused sports cars. Cue the 1990 Mercedes 190E 2.5-16 Evo II, which was limited to a production run of just 502.

The understated Mercedes rarity has doubled in price over the past five years and now sells for $515,000 (£400k).

In the realm of sports memorabilia, Babe Ruth has reigned supreme for a century, according to Antiques Roadshow appraiser Leila Dunbar. Artefacts that belonged to the baseball legend sell for bewildering amounts, with the mega-wealthy only too prepared to pay for a piece of his legacy.

The famous 'call shot' jersey Ruth donned during the 1932 World Series fetched $24.1 million (£18.1m) at a Heritage Auction sale in New York last year, setting a new record for the most expensive piece of sports memorabilia ever sold.

The value of Michael Jordan's memorabilia positions him as the closest competitor to Babe Ruth in the sports collectibles market. Wealthy collectors happily pay through the nose for items associated with the NBA superstar, which have shot up in value over the past five years.

Last year, the Dynasty Collection consisting of six Air Jordans the basketball GOAT wore in his six championship-winning games of the 1990s sold at Sotheby's New York for $8 million (£6.2m), a record-breaking price for game-worn sneakers.

Kobe Bryant is often considered the second greatest basketball player. Since his tragic untimely death in 2020, fans have been scrambling to honour his memory – and memorabilia from the illustrious career of the Lakers star has mushroomed in value. In 2022 for instance, mementos of the late shooting guard were selling for up to 20 times the prices listed prior to his passing.

Last August, Bryant's Staples Center locker sold for $2.9 million (£2.3m). This made it the most valuable sports locker ever to sell at auction, according to the broker Sotheby's. 

Mega-rich Gen Zs and Millennials who grew up with Harry Potter apparently won't think twice about dropping a ton of money on original pictures from the JK Rowling book series.

Last June, the original watercolour cover art for Harry Potter and the Philosopher's Stone by illustrator Thomas Taylor realised $1.9 million (£1.5m) at a Sotheby's New York sale. This is by far the highest price paid at auction for a Harry Potter item.

Knight Frank has highlighted the growing popularity of rare maps among the 0.1%. Ironically, it's the tech bros of Silicon Valley – pioneers of digital mapping – who are fuelling the obsession, driving prices for antique cartography through the roof in the process.

By way of example, a coveted map produced for a Chinese emperor by the Italian Jesuit missionary Matteo Ricci in the early 1600s sold for $1.9 million (£1.5m) in 2010. It's thought the map would fetch five times that number now.

From the sublime to the ridiculous, the craze for collecting Pokémon cards has reached a point where the uber-wealthy are shelling out unbelievable sums for the most sought-after specimens.

In 2021, the holy grail Pokémon card was bought by YouTube star Logan Paul for a whopping $5.3 million (£4.1m), the equivalent of $6.2 million (£4.9m) in 2025. Only 39 copies of the 1998 Pokémon Japanese Promo Illustrator Holo CoroCoro Comics card were ever produced, underscoring its extreme scarcity.

Collectible jewellery has appreciated in price by 33.5% over the past decade according to the KFLII, but growth has been lacklustre for coloured diamonds during the same period, coming in at just 3.8%. Other precious gemstones have fared much better though, including Kashmir sapphires.

Dubbed “a collector's dream”, they are prized for their rarity and intense velvety blue hue.

The planet's multimillionaires and billionaires are also crazy about Colombian emeralds, the most desirable for serious gemstone collectors and rookies alike.

A stunning 37-carat Colombian emerald set by Cartier and owned by the Aga Khan became the most expensive green gemstone ever sold when it changed hands for $9 million (£7m) at a Christie's sale in Geneva last December.

Completing the trinity of go-to gemstones for the super-rich is the Burmese pigeon blood ruby. The scarce beauty is renowned for its vivid red hue and exceptional clarity.

The best examples fetch jaw-dropping amounts. Recent sales have included a 10.33-carat ring that went for $5.5 million (£4.3m), though the most valuable Burmese pigeon blood rubies are worth tens of millions of dollars.

Now for some ruby treasures of a different kind. The pinnacle of classic movie memorabilia, the iconic slippers worn by Dorothy in The Wizard of Oz are the most sought-after items in Hollywood history.

Only seven pairs were made and just four survive. One pair sold at a Heritage Auctions event in December for an astronomical $28 million (£21.9m).

High-end watches appreciated in value by a mere 1.7% in 2024, but their value over the past 10 years has ticked up 125%, as per the KFLII. One of the most wanted timepieces among the jet set, the Patek Philippe Grandmaster Chime 6300 is the most complicated ever made by the Swiss watchmaker.

An exceptional version sold in 2019 for a record-breaking $31.2 million (£24.4m), while another formerly belonging to movie star Sylvester Stallone fetched $5.4 million (£4.2m) at a Sotheby's New York sale last June.

Guitars that belonged to long-departed music legends are a big hit with super-affluent collectors. Kurt Cobain's Martin D-18E holds the record for the most expensive example sold at auction – it went under the hammer in 2020 for over $6 million (£4.7m). But John Lennon guitars are undoubtedly having a moment.

The star's long-lost Framus Hootenanny 12-string guitar, used to record Help!, sold at a Julien's Auctions sale in New York last May for $2.8 million (£2.2m).

As we've mentioned, fine art depreciated by a painful 18.3% in 2024. But landmark works of surrealist arts are bucking the overall trend, with prices hitting unprecedented heights.

In November, René Magritte’s L’empire des lumières went under the hammer at Christie's New York for a staggering $121.2 million (£95m), over $31 million (£24.3m) above its pre-sale estimate. This result sent shockwaves through the art world, as it shattered the previous record of $36.9 million (£23.5m) for a surrealist artwork held by Joan Miró's Peinture (Etoile Bleue) by an astounding margin.

Specifically, the market for works by female surrealist artists is “on fire” according to Anders Petterson of ArtTactic, who is quoted in the Knight Frank report.

Last May, Les Distractions de Dagobert by UK-born surrealist Leonora Carrington was snapped up at a Sotheby's New York auction by Argentinian billionaire Eduardo Costantini for $28.5 million (£22.5m). The sale set a new record for both a female surrealist and British female artist.

Pop art is also proving remarkably resilient, as per the Knight Frank report. It seems the mega-rich just can't get enough works by the likes of Andy Warhol, Roy Lichtenstein and Ed Ruscha.

As it happens, Ruscha's Standard Station was the second most expensive artwork auctioned last year after Magritte’s L’empire des lumières. Billed as a painting that “defined the modern American landscape and contributed to the bold visual language of the 1960s,” it sold in November at a Christie's New York auction for $68.3 million (£53.7m).

For multimillionaires and billionaires who really want to make a statement – and perhaps even garner some publicity in the process – only the most bonkers conceptual artworks will do. Like surrealist pieces, they're selling for impressive sums, flying in the face of the overall art trend.

A case in point is Comedian, Maurizio Cattelan’s duct-taped banana (pictured), which incredibly fetched $6.2 million (£4.9m) at a headline-grabbing Sotheby's New York sale in November. The banana was bought by Chinese crypto entrepreneur Justin Sun, who ate it a week later, perhaps as a final edible act of performance art.

Famed for his controversial dead animal installations, provocative British artist Damien Hirst remains hot property and his artworks continue to go from strength to strength in terms of value.

Last October, a major sale of the artist's works at auction house Phillips in London wildly exceeded expectations, achieving double its pre-sale estimate.

Elite art collectors seeking street cred are keeping the street art market ever-buoyant. The anonymous Banksy, of course, is the best-known contemporary street artist and his artworks are in fierce demand.

Banksy's paintings are more valuable than his murals. His sensational Love is in the Bin, which wowed the art world when it self-shredded during an auction in 2018, sold for $25.4 million (£18.6m) in 2021, a record for the artist and the equivalent of $32.3 million (£25.2m) in 2025. And in March this year, Banksy's subversive take on Jack Vettriano's The Singing Butler was sold by Blink 182 bassist Mark Hoppus at a Sotheby's London auction for $5.4 million (£4.3m).

Vintage Vivienne Westwood clothing is trending with well-heeled collectors and has added cachet following the death of the grand dame of British fashion in 2022.

Quoted in the Knight Frank report, Anthea Pears of Christie's said a super-successful London sale in June, which featured important pieces by the late designer, was her highlight of 2024.

Vintage designer handbags appreciated in value by a modest 2.8% in 2024 but growth over the past decade stands at an excellent 85.5%. The last word in high-end handbag collectibles is the Hermès Birkin, which the uber-rich covet like no other.

At the current time, the larger 35 and 40 versions are appreciating the fastest, according to luxury fashion resale leader The RealReal, as recently revealed by Vogue. And while the fanciest finishes may sell for the biggest bucks, a classic Birkin in black Togo leather is a timeless fashion investment that's pretty hard to beat (if you have $20,000 (£16k) or thereabouts to splurge, that is...).

Quiet luxury that whispers rather than shouts is de rigueur among the more discreet UHNWIs. Take the minimal Margaux bag (pictured) from The Row, the ultra high-end fashion line from the Olsen twins.

A future heirloom in the waiting, according to Vogue, its value has tripled since 2020, with the understated piece of arm candy currently worth around $4,350 (£3,420).

Among the most resilient of the 10 collectible categories tracked by Knight Frank, coins have appreciated by 47.5% over the past decade.

Last November, a silver threepence minted in Boston in 1652 sold at a Stack's Bowers Galleries auction in California for over $2.5 million (£2m), obliterating the previous record price paid for a pre-revolution American coin by almost $2 million (£1.6m).

Roman gold coins have also been achieving enormous figures at auction.

In December, a Roman Imperatorial Brutus coin from 42 BC sold via NGSA for over $2 million (£1.6m). It ranks as the most valuable non-US coin sold in 2024. The most expensive Roman coin ever is an exceedingly rare gold version of the gold Ides of March denarius, also struck in 42 BC. It fetched almost $4.2 million (£2.7m) in 2020, the equivalent of over $5 million (£3.9m) in 2025.

Meet the 15 members of the 12-figure club, and five billionaires who could soon join them | lovemoney.com