[3.5] items for boosting knowledge and perform checks..

[animewatcha]

Be it WOTC sourcebooks, online archive, dragon magazine, or dungeon mag. No feats, martials stances, class features, etc. Just magic items. Which ones can boost knowledge checks or perform checks across the board. Like the Scrolls of Uncertain Provenance for knowledge checks.

[Osiris]

Lore gems give bonuses to knowledge checks, I believe.

[Gildedragon]

Tome of Worldly Memory

for Perform: Headband of Persuasion