I have a few.

PGR3, a Xbox360 racing game, contains Geometry Wars 1 and 2 as mini games. YT Link

Celeste contains the entirety of Celeste Classic (PICO-8) as an easter egg in one of its levels. YT Link

Xenogears, a PS1 JRPG game, contains a battle arena minigame, and I spent a few hours on that as a kid. YT Link

Machinarium’s 5 in a row minigame is so much fun, I played with my friends at school when we didn’t want to listen to our teacher :) By the way, I really recommend Machinarium to every fan of old school point-and-click games.