Ashtagon
Adventurer
If you're willing to put two levels into it, bard has a nice array of extra abilities.
Failing that, archivist gives Scribe Scroll and dark knowledge. Given the archivist mechanic, Scribe Scroll can potentially be really useful for a dipping warlock. Edit: archivist casts as a divine class. But the Scribe Scroll thing is still extremely potent for a warlock.
Failing that, archivist gives Scribe Scroll and dark knowledge. Given the archivist mechanic, Scribe Scroll can potentially be really useful for a dipping warlock. Edit: archivist casts as a divine class. But the Scribe Scroll thing is still extremely potent for a warlock.