In fact, roguelikes are my favourite games, but I find them thematically and mechanically really similar. Specially those tied to a traditional D&D-esque conception. Move around. Bump into things. Use potions with familiar effects.
Cogmind shines in its uniqueness, has robots, has ranged weapons, and many other innovative features (no doubt that makes it more difficult to balance and adds challenge to its development). Others like Deadnout do a mix of genres that I love, but there's a mountain of ideas that can be explored, aesthetically, mechanically and thematically.
When I imagine the roguelikes I'd like to play games I try not to think on the main tropes of the genre, dungeons, dragons and so on. Classic and cheesy sci-fi is my favourite source of inspiration. Three silly examples:
Them - Giant ants and the possibility of invading the cave system of an ant colony to kill the queen.
The Incredible Srhinking Man and its downscaling - but even more terrible - menaces.
Incredible Voyage and the exploration of the strange planet a human body is in a limited time.
I'm toying with Python and Game Maker, for a wartrain-themed roguelike with simultaneous combat (you decide your attacks, the AI decides attacks, shells fly, soldiers assault, the damage happens to both sides, if you win you reclaim the oppononent's intact wagons). Heavily borrowing from an oooooold game called "TransArtica".
Rexpaint is great to quickly give shape to those ideas. And as an art tool gets a lovely retro feel I adore.