They are technically against ToS. But SE doesn't really crack down on things outside the game so long as they're not used for harassment or egregious cheating. Some of the ones described in this thread like the hunt radar and that PvP one definitely sound like some that SE needs to look into. Anything related to botting as well.

I don't ever think that SE is going to acknowledge any of these officially or start content around their use. They've been pretty firm on their stance on that. They just turn a blind eye since some in the community find some of these useful and so long as they're using them responsibly, they aren't going to rake anyone over the coals.