As far as casting in AMF...

The Initiate of Mystra feat allows you to cast in an Antimagic Field, as does Invoke Magic. The Twice Betrayer of Shar is a build that uses this sort of AMF abuse as part of its shtick.

Other things that only sort of count:

Certain spells, like Wall of Force, Prismatic Wall/Sphere, and most instantaneous conjurations can be cast into an AMF (from outside the AMF).

The Archmage's Mastery of Shaping and the Extraordinary Spell Aim feat both allow you to sculpt an AMF so that you're not technically in it.