A few of my favourites:

Darklands (1992) - one of the OG RTwP games. Fairly low-fantasy, you play a mercenary gang, doing mercenary things. It's quite old, and like lots of games of its era, is very obtuse, and not a lot of information is available in game, but if you can get past that, it's a great game.
The Elder Scrolls II: Daggerfall (originally 1996, but I recommend the Unity fan-rewrite Daggerfall Unity) - Procedurally generated dungeons and wilderness, an absurdly huge world, much deeper skills and stats than later entries in the series. It's not my favourite in the series (that goes to Morrowind) but Daggerfall is certainly definitely worth playing, and the Unity re-write (with mods!) makes running the game a breeze.
Ark Fatalis (2002) - underground first-person RPG, with a very unique magic system, incredibly immersive environments (one of the least "game-y" worlds I've experienced in a game), and a branching story affected by your choices. It was open-sourced a few years back, and a community has formed around a continuation of it, known as Arx Libertatis.
Gothic (2001) and Gothic II (2005) - third person RPGs made in and very popular in Germany. Another pair of incredibly immersive RPGs, way ahead of their time in many aspects. The towns and cities all feel very lived in, and the NPCs themselves feel more alive than even some modern games (looking at you Cyberpunk). The character progression is absolutely fantastic, as is the way of levelling up skills and stats. Much more immersive than just "watch number to up". As with Arx, there is some plenty of that early 2000s jank, and extremely wonky KB+M controls, but there are mods on that add controller support, and various other modernization/QoL features as well.
Star Wars: Knights of the Old Republic I (2003) and II (2005) - Star Wars RPG taking place thousands of years before any other established stories. Very open ended in both story and character progression. It's like a Baldur's Gate in 3D, but Star Wars. The first is fantastic on its own, but the second needs the Restored Content Mod.
Divine Divinity (2002) - from the people who would eventually make Divinity: Original Sin. Diablo-style combat, loot, and inventory management, with classic-cRPG-style questing, story, and character progression. There's also a follow up, Beyond Divinity, that I haven't personally played yet, but I imagine is more of the same goodness.