Work Smarter, Not Harder
It would take a lot of time and effort to cheat your way into enough feats to learn everything the 'right' way, both in and out of character. But since you're not being limited to official sources anyway, why bother with all that effort? Just take what you want!

Prereq: must possess at least two flaws that minimally impact your playstyle
Effect: You instantly learn every spell and power that's ever been written for any d20 system compatible with D&D 3.5 edition. That includes PF1, d20 Modern, FFd20, homebrew nonsense - all of it. Additionally, you gain one bonus feat.
Special: Ain't you just?