Ever hear the one about the 11-year-old who nabbed a one-of-a-kind baseball card of rookie of the year Paul Skenes? Or how he rejected an offer from the Pittsburgh Pirates, which included three decades' worth of season tickets behind home plate and a meet and greet with Skenes himself?

The young Los Angeles-based collector has instead decided to put this tiny piece of memorabilia up for auction, where it is expected to fetch a six-figure sum. Welcome to the bonkers world of Topps trading cards.

To say these prized assets are sought after is an understatement. Another U.S.-based collector called Alex could not believe his luck after unearthing a one-off Alan Shearer card in a $220 stadium chrome box in his local shop in Texas a few months ago.

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"My heart just stopped," the 20-year-old told ChronicleLive. "I was in shock. I know it sounds silly because they are just cards but, mathematically, those odds are so astronomically small."

The card has been personally signed by Shearer - it is a certified autograph issue - and captures the Newcastle United legend in action in his final season before hanging up his boots in 2006. It is not going to command anywhere near the sort of sums that Skenes' equivalent will, but Alex took it along to the Dallas card show in the U.S back in November to get an idea of its value on the market. The university student ended up receiving some sizeable bids.

"They offered me a wire of $1,500 and I told them I didn't think I could do that," he recalled. "I had someone offer me a Lamine Yamal rookie autograph card plus $600 and was like, 'No, I can't do it.'

"It took being headstrong in keeping this and getting to this point. I did have those offers, but I just couldn't accept them. When you have one of the greatest players like that, it's really hard to let go of it when it's a one of one card."

Alex instead set about, somehow, tracking down all the other marks of excellence Shearer cards from the series to complete the 'rainbow'. This meant finding the one of five; the one of 10; the one of 25; and the one of 50 cards, which each have a different colour frame surrounding Shearer's portrait. Hence the term 'rainbow'.

It was not straightforward. Sourcing the one of 10 proved so tricky that Alex wondered 'if it was real' and the collector even messaged Shearer on social media to ask the Premier League's all-time leading goal scorer if he remembered signing it.

Alex eventually found the missing piece to complete the set, which he estimated cost around $1,970 (£1,583) to put together. Although the overall haul is now worth at least double that figure, the student wants to hold on to the 'one of a kind' collection.

"Could I sell this whole thing now for $4,000? Yeah, to the right person, but it's not worth that to me," he added. "Unless the offer is outrageous, I'm keeping these for the rest of my life."