Collecting all mementos in Hollow Knight: Silksong is a true mark of someone who's embraced every endgame challenge they could find. These eight souvenirs come from various late-game bosses, quests, plus platforming and movement puzzles, allowing you to display them in your Bellhome once you've earned each one.
They aren't strictly necessary (I'm not sure they all count towards 100% completion), but each one is a challenge you'll want to encounter if you're a completionist. These mementos aren't available until Act 3, mainly because the quests don't spawn, or you don't have the relevant movement abilities like Silk Soar.
