For me, I'd have to say Old School X-COM (UFO Defense, TFTD, X-COM Apocalypse to an extent). I love them in a way that I just do not enjoy NewCOM, but the interface was quite possibly based on the recovered works of a 13th century scribe, and is very difficult to get used to for an unfamiliar player.
I'm actually going to completely disagree and say that turn-based combat is timeless. Sure, the specific implementations in those games were perhaps limited by the technology of the time, but if you play a game like Paper Mario TTYD you see a very smooth and engaging turn-based battle experience. I feel like real-time battling was just pushed so hard because it was something they could brag about, but in pure RPGs it often isn't really that relevant. I'm going to ignore the question of turn-based tactics since that's very obviously a different ballgame, but even for these simpler fights there's a lot to work with. Even in more of a pure menu-based system games like LISA for example had really engaging combat.
As someone currently really enjoying Darkest Dungeon II hard agree
DQ11 has great turn based combat.
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Exactly! The reason it's so common in RPGs is as essentially a filler to keep it from being a VN, and to control pacing. The real draw for a lot of those games is meant to be story/setting/characters and the combat is fine as long as it's just kinda ok.