This was actually a great thread for a newbie like me to select RLs to start off with. Started off beginning of this year and played and finished TOME4, Zorbus, and DCSS. Now I'm playing Angband, and I have Caves of Qud, Infra Arcana, CDDA, ADOM, UnRea World, DoomRL and Sil-Q to try out . The only one I've played and it didn't really do it for me was Brogue.
I sense problems at the horizon. CDDA is more an open world slash surviva slash RL - and it doesn't have any endgame. Not sure in case of Unreal. Also CDDA uses the same keyboard shortcut conventions that standard RLs use but it has a lot more complexity than most RLs. Read: it is a pain to remember all keyboard shortcuts you need. But well worth it. The game is huge. The vehicle buildng and driving "minigame" (not really minigame, it is 100% integrated into gameplay) alone could be a small game in itself and wouldn't be a bad one.
What about Incursion, despite being unfinished it supposedly is an interesting RL.
Also why not Nethack?
In addition I propose trying Wazhack. It is a weird simplified version of Nethack - but by no means simple or easy. Weird because it has very different presentation like many rogue-lites. It is turn/phase whatever based though it might look real time at first glance. Make no mistake, this one is a true RL minus the view perspective.
Don't feel the need to try Cogmind?
What about IVAN? At least for some lulz. Though it is finishable. Right? Anyone who played a lot can share a thought?
I didn't like Brogue for some reason as well.