Tab Mix Plus replacement

Firefox users, what's your favorite Tab Mix Plus replacement? I'm still clinging on to Pale Moon for a variety of reasons, but am starting to get very tired of the way it tends to choke on sites like DeviantArt and Facebook, dealing with "your browser is out of date!" nagging because websites don't recognize it (or having to try to keep up on tailoring fake Firefox useragent strings), and actual non-functionality of some websites. One of the things I don't want to give up is TMP-like tab managing, but though I held out hope for a while that it would be updated to work with whatever extension packaging it is Firefox uses now (since the browser tab it would open after updating asked for donations to support that development), I think at this point it's definitely been abandoned.