Game Pass is particularly ideal for two kinds of games: indie games you're not sure you'll like enough to commit to the upfront cost, and decent-not-great blockbusters you know almost certainly aren't worth the cost but would quite like to play for at least a bit.
There are plenty of games that fit into both of these categories joining the subscription service before the end of May, including Vampire Survivors, Hardspace: Shipbreaker, Sniper Elite 5 and Jurassic World Evolution 2.