This group includes games officially based on the famous tabletop RPG Dungeons & Dragons. Often. considering that we are talking about games released in the 80s and 90s, we are talking about Advanced Dungeons & Dragons (AD&D) and the iconic 2nd Edition.
The first game to use the D&D license was SSI's Pool of Radiance (1988), the first of the so-called Gold Box series, set in the Forgotten Realms. Champions of Krynn used the same engine but was set in the Dragonlance universe.
The legendary dungeon crawler Eye of the Beholder and the sequel Eye of the Beholder II: The Legend of Darkmoon were set in the D&D Forgotten Realms. While the first Genesis game to use the D&D license was Dungeons & Dragons: Warriors of the Eternal Sun, set in Mystara. Completely different settings for Dark Sun: Shattered Lands, a fantastic turn-based RPG set in the desertic Dark Sun universe.
Even if most D&D games were RPGs, we have other examples, such as the turn-based strategy game Fantasy Empires or the flight simulator DragonStrike by Westwood Studios.
It doesn't matter which one you choose. All D&D games are excellent choices, and they are among the most beloved titles by retro gamers.