Linear: has to be hall effect switches, linear space invaders, or maybe green alps. I think the place where I most would want a linear switch would be some kind of music input keyboard with analog sensors for each key.
Topre: Topre switches are totally uninspiring, and I wouldn’t want to actually use one on a regular basis. The μTron is basically the only Topre keyboard that is interesting to me, but not very practical for someone who doesn’t have tiny hands. It’s really silly to make this a separate category, since Topre switches clearly fall into the “tactile” section.
Clicky: tough call. Between blue Alps, Model F, Alps plate spring, Marquardt “butterfly” plate spring, etc., it’s hard to pick just one. To be honest I’d give up all the other categories and just go for 4 different clicky boards.
Tactile: if it’s just one board, it probably to be orange Alps. But a very portable folding lubed Cherry ML board could also be pretty fun.