At the moment, the pages that come up under the Tags tab display synonyms at the end of the list. There's little indication that they're synonyms; they look just like any tag that's used once. Only alphabetization on the page where the single-use → synonym switch occurs gives any indication that certain tags are synonyms at all.
We already identify tags that are used multiple times by appending a number, like "× 574." Can we append something similar for synonyms, like "× 0" or "(s)"?