So these are some suggestions that could be used to expand the mod, including upgrading other armors, and stuff like that

Marble Suit, Two branched upgrade:
Idea with this one is to have two upgrades for the marble suit, one that increases the durability, nothing super fancy, probably made with gold & flint, bulking it out
but another branch featuring Moonrocks, which has the same protection and durability as marble suit, but without the slowed movement speed

Thulecite Suit, Big project for epic rewards
the idea for this armor is for it to be a resource sink, requireing a bunch of stuff, but to upgrade it into extremely powerful armor, inluding the end-game goal of making it unbreakable! (requiring extremely hard-to-get resources)
this isn't a one-off upgrade hoever, but progression though the tiers of thulecite suits.