Hmm, these would fall into quite a few categories I think.
Outright broken - Not playable, as in, REALLY not playable. Not much falls in here but for infinite loops and anything that gives something for nothing.
Too much possibilities - Shapechange, PAO, Planar Binding, Wish, Shadow <foo>, Rainbow Warsnakes. Not outright broken, but rather they can do anything and everything. Which is a pain for a DM to have to deal with AND a pain for the player to play true to form.
Rocket Tag - If I could fix this without changing the game entirely....this is all stuff which puts it all down to one roll or ludicrous modifiers for the level. Ubercharging can fall here, though most ToB stuff doesn't really.
Too Good/Bad for the level - level inappropriate abilities. Generally covers spells and stuff that regularly outperform 90% of similar level effects. Lots of eyeballing to determine what is the norm for the level though.
Hello and goodbye Action Economy - Extra Actions. That is all. A lesser subclass might be allowed for Limited extra actions, which let you perform something highly specific(quickened magic is not highly specific, but given the cost, is usually ok until you can spam it or if you can combine it with one of the other bad cases)
Campaign breaker - Teleports, 'True' Divinations, stuff that basically shreds campaign premises. These depend on the game, but it can be so easy to bypass the whole adventure.
