https://support.strava.com/hc/en-us/…Activity-Types
Vote Early, vote often 
It is a bit of a silly website where you basically have to downvote everything else. That is… unicycling is the only sport that interests me.
It does seam to be rather pointless as everyone likes are different,not for me thank you!
That’s been going on for years now. When it started, we all got excited because it felt like finally, Strava was listening to us asking for a unicycle category. But after having been sent this poll many many times now, I gave up. They just keep doing that to make us feel like they care about sub-categories.
Maybe the problem is that Garmin doesn’t have a unicycling activity type. Strava seem to have a partnership with Garmin above and beyond other data providers. If Garmin added a unicycling activity maybe Strava would adopt it.
Also, lately Strava seem to be interested in adding new features. Maybe now is the time to ask for favours.
While voting on the forum, I did wonder though why I even care. I use MapMyRun when tracking my distances, not Strava. I don’t take my speeds too seriously. Sometimes it gives an idea about what I can do, but mostly I just ride because I like it. My longer rides are mostly when I don’t feel like going home yet. Also my average speed calcs aren’t 100% accurate as I start a run, then put my phone in the backpack and then mount, which doesn’t always work the first time, so I will always have some loss in the first kilometer. It is good enough to get a little bit of an idea about my cruising speed.