Hoo boy, there's a bunch, hell, I even have a folder dedicated to the damn things. But instead of going trough the entire damn thing I'll just shoot off some examples.
Starting off with
Stellaris - Birth of a star, the whole soundtrack is amazing really, but this piece in particular is fucking magical in the most literal sense, I don't even play the game anymore but this particular song has become something of a safe space so to speak.
Then there's the
C&C Generals which is just amazing trough and trough and an excellent example of how to themathically differentiate factions, even trough music, this isn't just different songs this is whole genres of difference, each of them brilliantly used to convey both the faction and the gameplay.
From Sim City 4 there's
Terrain, you know you got something good when the particular song is used in tv shows and the like and the intro is so damn recognizeable that it jumps out at you every time you hear it. The rest is stellar work too, creating an amazing ambiance of a living city. (on a side note, is it just me or does EA usually have stupidly good people working their music)
Risk of Rain has a damn good soundtrack too, especially the final piece,
Coalescence. It's hard to explain too well unless you've played it, but the damn thing has that something special that just kicks the final level into overdrive when it comes to atmosphere and it feels almost painful at times, tho it could be just me getting too much into music :V (related, the song is on the authors channel, he also did the Deadbolt OST (also damn good) and he has some breakdown videos where he goes trough the soundtracks he did and explains the thought and creative process behind them, great stuff for anyone interested in video game music or just music in general)
Then you have the enitire Age of series, which not only have amazing soundtracks but some of the best soundtrack titles out there, like say
Smells like crickets, tastes like chicken, another neat thing is how the sound evolved trough the games while the main sweeping themes are still clearly recognizeable in one form or another, kinda like what Soule did for the Elder Scrolls series.
Now there's a bunch of others but this post is already a Trump sized wall of text so I'll just name some others shortly, you can prolly find them on YT. Battle Realms, damn nice game with a damn nice soundtrack. Anything by Supergiant games (that is, Bastion, Transistor and soonish Pyre which I just know is going to have great music). Journey has some nice sweping pieces. Any of the Dark Souls games. Anything Klepacki has touched, tho I can't recall what was the last game he worked on, RA3? Warcraft, namely 3 and onward (haven't played the older ones enough to remember the music), WoW has some damn nice tavern tracks which are good for general chilling around.
And many many others that I can't be assed recalling atm.