i'm looking for a way to filter lists of any of entries, authors, etc.

Taking a look at the filter categories plugin this has been added to the way category lists are filtered.

i know this can be used in listing authors but since there is already an authors plugin maybe it can be added to this instead.

maybe this is something pluging writers should take a look at. if the plugin produces a list of some sort that cannot be filtered using exiting MT tags, exclude and include filters could be provided.