I generally run a minimum of 1 each of Dispel, Disperse, Seeking Dispel and Purge Magic. Only Warlord doesn't carry that at a minimum, and quite a lot have more.
Similarly, in an anti-equipment role, almost every book has 1-2 Dissolve, Crumble, Disarm and Acid Ball. Probably 6-8 total, with number and configuration depending on what the book needs to do.
Arcane and Water mages run more, as do some other mages.