*Rayman series* - 's groovy. Rayman was my childhood. The composer for the first game recently did/started doing full live orchestra arrangements of its soundtrack. Pretty cool.
Rayman 3 because it's honestly the only other one I'm really familiar with: … Geez the full OST is 8+ hours, check comments for timestamped list, favorites include Hoodoo Sorcerer (+ Credits, alternate version used for only one encounter), Mecha-Squid, the Shortcuts, Funkyboards, Land of the Livid Dead, the Summit Beyond the Clouds - https://www.youtube.com/watch?v=N9cUAGcXVho
*EDGE* - Spacey little bloops. Fits the sharp, blocky aesthetic of the game.
*Dance Dance Revolution* - DDR had the largest impact on the formation of my early musical tastes out of anything. There's been THOUSANDS of songs in DDR games at this point. Just listening through a mix's song list previews takes about fifteen minutes. There's no short list. Styles are all over the map.
Konamix is an old mix, but it's relatively short, all original music, has a number of classics, and is what I grew up with, so - https://www.youtube.com/watch?v=dAnvuw7H6I4
*Undertale* - Theoretically interesting, brilliantly intertwined cobweb of leitmotifs, complements each moment of the game beautifully, some fun Easter eggs for the musically inclined. IIRC, for a lot of scenes, the music was composed before anything else.
I'd single some out, but there's about a dozen equally top-tier tracks, some with leitmotif spoilers and some much better in context/at the in-game speed rather than OST (slightly different in some cases). Just play the game if you still haven't (fanbase-induced hype aversion sucks right?) and hear everything in context.
*Katamari Series* - What would Katamari be without its ingeniously eclectic soundtrack? NOTHING. IT WOULD BE NOTHING. Except a fun game with no soundtrack.
*PS1 Spyro trilogy* - Composed by the drummer for The Police, Stewart Copeland. Mystical and oddly idiosyncratic. Since I mentioned Undertale's music often came first, I happen to know the music in Spyro was built around each level.