a nice undertale-themed map made by 8bitsandwich with a cozy nighttime feel. you can head into of a UFO too. the only link i could find for it nowadays redirects to the gmod version, but i think it should work since it's a port of the TF2 version.
i also tried finding a copy of the ed edd n eddy map to post here as a suggestion, but i could only find the gmod workshop page for it, so that sucks.
Two nicely detailed VSH maps made by the creator of vsh_gyros. Both maps have a really nice theme and detailing. The architecture and textures of the buildings remind me a lot of Dishonored. Both layouts look unique, should be way more interesting than bland huge open arena maps.