There are many. I usually use this list myself.
For Knowledge (Psionics), there are many options: Education (Eberron Campaign Setting version) gets all of them, and Apprentice (philosopher or spellcaster) (Player’s Handbook II) or Knowledge Devotion (Complete Champion) gets any of them.
Use Psionic Device is harder, though. There’s Skill Knowledge (Unearthed Arcana) but that’s dependent on DM allowing it even if you aren’t using the variant rules that introduce it. The Flexible Mind feat that @Novian found also could work.
But a much better answer would be to ask your DM for a Manifester option on the Apprentice feats. Apprentice (Spellcaster) gets you any Knowledge, and Use Magic Device. Apprentice (Manifester) would therefore get you any Knowledge, and Use Psionic Device. Totally appropriate, and much better. Plus it turns into a mini-leadership at level 5, which is cool. The Apprentice feats are solid.
For the Anarchic Initiate, my first advice is to burn your copy of Complete Psionics; it’s almost-entirely awful. Barring that, I’d tear out the pages with the Anarchic Initiate. And if you won’t do that, hopefully at least your DM is smart enough to see that it’s really dumb that Psions get in far more easily than Wilders and change the pre-reqs.