Hard to pick just 1, so here's a list of ones I deem notable from a few different games:

• 14.3 Billion Years — Outer Wilds
• Undertale — Undertale
• City of Tears — Hollow Knight
  • (with in-game ambiance)
• Under the Eye of Kibenya — Heaven's Vault
  • No publicly available version of this one; but the game and soundtrack are good, so they're worth a buy
• Private Room — Five Nights at Freddy's: Sister Location
• Tiny's Theme — Mario Golf
• Cleopactra — Ms. Pac-Man Maze Madness
• Dive Into the Mellow — Sonic Adventure 2
• Fathomless Tomb — Deep Rock Galactic
• They Might As Well Be Dead — Risk of Rain 2
• xX_TF_CNS_FloatingBits_Mp3_Xx (Floating Bits) — The Finals