I have a classic in mind that I never hear anybody talk about, but "forgotten" would imply that anybody had heard of it. Or, anybody outside of the UK, anyway.
It's called Bolo, which launched for Macs in the early '90s and on the BBC Micro in the UK before that. Top-down tank-battling versus combat, designed for networked computers, with support for up to 16 combatants. My middle school computer lab had a group of 16 networked Macs, and someone on our school's staff was clearly a dork because he installed this on all the Macs so that kids could engage in deathmatches during off and lunch periods. This, I must remind you, was well before networked combat became viable, let alone popular. (Our labs also had licensed copies of SimCity 2000, and kids would write PORNTIPSGUZZARDO on the chalkboard frequently, which teachers would erase without realizing that was a major cheat code and we were just sharing it.)
[EDIT: The above video is from WinBOLO, a version of the original that has proper TCP/IP support for modern computers. No idea if/how it works on, say, Windows 10, but I recall it working fine on Windows 7 a while back...]
The other forgotten classic I like to think of is Iggy's Reckin' Balls.
There aren't really many examples of "platformer racers" out there, other than Sonic R (yikes) and Uniracers (hmm). Iggy's takes the genre cake by default, and I count it in the genre because of the game's grappling-hook power. Acclaim published a lot of garbage on the N64, but this was right up there with Turok and Xtreme G as far as their N64 output was concerned. I'd love to see more speedrunners take this game on. (Action Henk, if you know about that delightful game, lands somewhere halfway between IRB and a standard Sonic platformer, I would say.)