My question is what are limits for such a superuser?
There aren't any. As long as your answers are consistently judged by the community (via votes) to be of high quality, no rate or post limits are set for users.
Low reputation users have timed post limits (see The Complete Rate-Limiting Guide for reference), and if answers are consistently judged as poor ...
Thanks to various users, the filter tag is now burninated. All that remains of my original request is the proposal for stackexchange-filter (13 questions, no excerpt/wiki) to be a synonym for tag-filters (154 questions); you can vote for it here.