Can someone give me a rundown on what items are worth keeping to trade, and what I should charsi (or loot filter out)? Are white bases ever good, or does the low socket count mean I should only check rares?

+3 Abyss with 3 Socket daggers are pretty much it. Anything extra is a bonus.
They're good for Void runewords.

Besides the unique Tome's, i don't think any of them are worth keeping for value. Only really useful as self use for Rhyme or Splendor runeword really.

so.. there is something called Spirit and it makes those obsolete

some people use +6bind demon book and +6bind demon dagger to save skill on bind demon

Ok, so white tomes are getting filtered out. Are you saying rare tomes (like +2 warlock +3 specific skill) are also outperformed by spirit and/or the uniques?

For the most part yes, the 1 that give up to +7 apoc with increased fire dmg and the other with 2 skills 30fcr an -magic res r actually strong an hard to compete with, u would need to find +5 good kill skill with a second or third support skill with a combo of 30/20, 2os, life, res etc

So not saying all are useless but u gotta have some next level luck to actually find 1 worth using over the options and have a value