PrCs for "civilians" and noncombatants

[Prime32]

Psi-Hunter (Dragon #281) generates a continuous catapsi aura, is immune to detection by any psionic ability, can create a permanent null psionics field, and has 5 levels of useful spells including antimagic field, dispel magic, globe of invulnerability, spell immunity and true seeing. It can explicitly use these spells against psionics even when the "Psionics is Different" variant is in play. In theory you could take Don Mantle (Magic) to hide from all magical detection as well.

Windsinger (Dragon #294) gets forms of bardic music that can be used continuously for hours at a time (or indefinitely if you're immune to nonlethal damage). Most of them are related to controlling wind and weather conditions, but there's also an option which prevents listeners (other than the windsinger) from receiving fatigue, exhaustion, or nonlethal damage from over-exertion.