My road and gravel bike have the same saddle (in different colors). My single speed - which incidentally, has probably the most aggressive geometry of all my bikes - has the saddle I used to use on my road bike before I found one slightly more comfortable.

My winter bike/trailer haulin' rigid MTB has a slightly wider and softer saddle. It makes sense for shorter rides where I'm a bit more upright, and does a bit better without cycling shorts.