Some harassment comes from anons, as was this case with https://en.wikipedia.org/wiki/Special:AbuseFilter/792

It'd be great to allow not only entering in IPs, but also IP ranges. Right now for the above example, if I want to see if there are interactions, I have to enable the filter and wait to see the results (or painfully cross-reference using Special:Contribs). This means we have to employ the expense of a filter solely for observation purposes. If I could check for interactions ahead of time, I'd be able to play around to find out which IP ranges need to be targeted, or discover a filter won't be useful at all.

Introducing this feature might be a bit challenging on the frontend, but the backend shouldn't be so bad. For single IPs, you can use rev_user_text (which you're probably using now).

For IP ranges, you can take advantage of the ip_changes table, and target a range with something like ipc_hex BETWEEN 1234 NAD abcd (using hex IP values). If/when you get around to this, I'm happy to help :)