Strive for Power (actually 100% finished), Strive Conquest (alpha sequel, getting semi-regular updates still), CoC1 (officially 'complete' despite having no ending and abandoned for the sequel, modders keeping it alive), TiTS (alpha, still getting updates), Masters of Raana (alpha, no non-Human characters, still getting updates), Fort of Chains (another 'completed' game that has no ending and was abandoned, don't know if modders are trying to keep it alive), No Haven (uses an obnoxiously old engine that requires special software, but is finally being converted to Twine after being promised for years; updates so slow most people consider it a scam at this point.)
There are probably some other similar games I've forgotten, but those are the standouts I've tried. While not quite the same genre I'd also recommend Portal of Phereon all day. It's a sandbox RPG with monstergirls, lots of customization, has actual endings, and is very close to being 100% complete.