Reading "Collectors are as confused as you are about that $1.56M Super Mario 64 sale" made me curious. What you'd expect from a collector is this: "the biggest collectors generally wanted to own a complete, playable set of all the titles on their favorite platforms." And, of course, "as these completionist collectors got near the end of their checklists, they all ended up competing for the same rare titles. [...] For these completionists, the fact that these titles had little-to-no intrinsic value in terms of nostalgia, gameplay, or historical significance was beside the point."
Or in simpler terms: when it comes to collectors, you have deep pockets combined with a tendency toward a lack of rational decision-making. That urge to complete your collection is strong. So what are problems worth solving in this area?
First up, a disclaimer. I'll focus on tangible assets with "real, physical" scarcity. Everything around digital collectibles, especially non-fungible tokens, is a different topic. That being said, let us do a quick research and idea briefs.
When it comes to competition, have a look at the Online Auctions and Collectibles hubs at Crunchbase. Yes, there is competition. There always is. But take these lists, for example, and cross off those that cover digital assets/ blockchain stuff and you'll get a different picture. In addition, a search on Indie Hackers does not show any product about collectibles.
The ideas above are all rather generic. Always remember that for indie hackers, serving a niche is important. And when it comes to collectibles, there is a market for everything.