Procedural generation is an interesting topic to me, as it forgoes traditional level design in favor of a bunch of formulas, rules, and random elements to make varied replayable gameplay.
One of my favorite procgen games is Dwarf Fortress, and how it creates a fully realized world with lore and history, and then places both fortress and adventures as relatively small stories in said world.
Also Deep rock galactic is great in varying its caves, from normal tunnels to massive caverns that you can only traverse using ziplines and platforms
Nethack, Elite, Captive, Elder Scrolls, Magic Carpet, Simcity 2000 (reticulating splines)... oh, and a little game called Minecraft.
Procedural generation is common. The way Dwarf Fortress does it where the rules and game elements change is nearly unique. Pretty much just that and Nethack, AFAIK, which is why Dwarf Fortress stuck with Nethack-style ASCII so long.
The first two games, Arena and Daggerfall, were both procedurally generated on the fly.
Later games have been more of a "procedurally generate the game geography using perlin noise, freeze it, then paint the valleys, roads and cities onto it" approach. Not dynamic generation but not handcrafted from scratch.
I guess they had the radiant quest system, but it wasn't very impressive. None of the dungeons in Skyrim were proc gen, unlike how they were in Daggerfall.