How to use the Alliance spell and/or illusion to avoid KoS

[REMEZ]

Many factions are not fixable, so results may vary on what and where you already have killed:

Velks lab - WW form + Collaboration (triggered traps will still agro)
Sol A goblins - Alliance (handy when buying Tinker bags for 5039pp)
Brownie settlement in lfay - Earth illusion
The Hole - Elemental illusion + Alliance(Rats, undead and yael still kos?)
Sirens Grotto - Alliance
Oggok - Skeleton Illusion
Thurgadin - Dwarf Illusion raises faction
Wolf Illusion in Firion Vie will make you KOS to some NPCs in the outpost

Often you can bring a mob from threatingly to non kos with alliance/collab, wave that rod at everything and see what happens!

As a agnostic enchanter you can visit all cities with the right illusion except for Cabilis that I know of, Cabilis SK guards will still kos you in iksar illusion.

In reply to -Catherin- note " The bard has to be carefull with this where a chanter can just increase every faction in the zone if they wanted to."

I find this not to be correct always, the one example I can think of is the Bulthar in CS vs the sirens on SG faction, I noticed this when charming bulthar to kill sirens that I would go kos to bulthar after clicking alliance on siren.