For the consumables that permanently change a knight I was thinking some of them could be special items, for example you defeat a junk bug type enemy that is carrying some loot and you may find some old tome with forgotten history or magic that promotes your intellect or gives you +1 emblem and +1 emblem slot. Or you venture into some secluded area and find an NPC that recognizes your strength and gifts you an elixir that promotes your might in return for fulfilling a request to prove your strength by freeing them of some accursed spider that has been preventing them from leaving. Just some ideas for the permanent change items. for some of the other special items maybe some of the descriptions have hidden benefits like a silken may help you hide better from spiders when you are in their lair and surrounded by their webs of silk, or an antenna mask may have actual antennae sticking out of it and hide your appearance better giving you a temporary promotion to presence when talking to other creatures. stuff like that was what I was thinking.
Subject to change but take a look https://docs.google.com/document/d/1GLH0oDVutWUzus_RH6UgC0c8-9ZzRm_GIZUE85s02Rs/edit