Gurps: The generic System
Gurps, short for the Generic Universal Role Playing System, is well deservedly famous for being one of the most vercitile systems. Gurps does this by trying to catagorize every possible skill that any charecter could have or need and then allow the Dungeon Master to figure out which skills fit best within their world. This allows for a very vercitile, and very complex, system.
Gurps has many descendants, many systems that are made for generic roleplaying and some systems that use Gurps' ideas and create a specific setting system out of them. Perhaps the most famous is the original Fallout Special System, which is the game system created for the original Fallout video game when Gurps went out the window. The special system is fairly similar to Gurps in a lot of ways, and simply uses its ability to go from the ground up to ground itself in being specific for the Fallout setting.
Another descendant of Gurps is an actual generic system, Fate. Fate is well known among RPG enthusiasts, mostly for its unique system of Dice. Fate dice are six-sided dice, each of which have two sides with pluses, two sides with minuses, and two sides that are blank. This makes a very math-minimal system that quickens gameplay and allows for the Roleplaying to be the center stage of the game.
Cyberpunk, the Genera Definer
Cyberpunk is one of the most Genera defining games of all time. While Cyberpunk was a common setting for the decade leading up to the game, it still Codified a lot of what people think of as Cyberpunk. The corporate shenanigans, the road warrior style outlands, the cities that are at once technological marvels and complete garbage fires. Cyberpunk was able to create a very raw experience that anyone who enjoyed Science Fiction and RPGS.
While others exist, Cyberpunk is the most famous of the Sifi genre RPGs, which are often stereotyped as being fantasy due to their origins with DnD. Cyberpunk helped to re-kindle the genre and keep it alive for alot of people through the 90s, after the 80s which were the highlight days of the Cyberpunk genera.
Interestingly, Cyberpunk just got a reboot this year in the form of a brand-new video game. Along with the video game, Cyberpunk 2077, a new edition of the classic Tabletop game came out known as Cyberpunk Red. This served to coincide with the video release, acting as a sort of prequal taking place between the events of the old setting Cyberpunk 2020 and the new Cyberpunk 2077 setting.
World of Darkness
World of Darkness is one of the most expansive of the Table Top RPG games, not in scope but in compatibility of play. World of Darkness is set in an archetypal urban fantasy, or as they term it Gothic Punk, setting. The games were most famous for the Vampire the Masquerade sub-game, the interactions of which sometimes grew to a national scale as the creators created interactions between player groups.
Vampire the Masquerade was also a fairly popular live action role playing game, titled Mind's Eye Theater, to separate it from the main World of Darkness games. Mind's Eye Theatre included the other games from World of Darkness, but none were so common as Vampire.
World of Darkness, and specifically Vampire the Masquerade has continued to be updated and re-released with new art and altered rules for more than twenty years. In fact, there is a twentieth anniversary edition and a 5th edition, both of which are recent versions of the game.
World of Darkness as a whole got a reboot a few years back with Chronicles of Darkness, a new simplified game that allows for a lot more cross play between the different sub-games.