There are a lot of video games out there. Some of them are known by almost everyone, but in such a hit-driven industry most games aren't remembered. Unless you shared the exact same consoles at the exact same time, you're likely to have at least one game that you've played but most other people haven't. GOG has been doing a great job of bringing out-of-print games back, but there are a lot of games still missing. Some are practically inaccessible now, because of their clumsy interfaces or dated presentation, but odds are that you know of at least one game that is worth talking about.
I have a bunch of examples that fit this description, because obscure gaming history is one of my interests, but for the same reason I'd like to hear what obscure games you know about and I don't. Whether they're underrated gems, obscure bits of gaming history, or just games that won't get their own thread because they were released two decades ago but you'd like to talk about them anyway.