I've played many games over the years so it's hard to just pick a few games I like the most. Some of my favourites in this list are either because of they are nostalgic, some are emotional and/or have a great story, some were technical advancements, others were just plain fun.

Baldurs Gate 1, 2 & 3
Yes, BG3 is great but quite a bit different from 1 and 2. Still, I love all 3 of them amazing story and writing.

Dead Space 1 & 2
Perhaps not as unique now as it was back then but these are some of the best survival horror games out there.

Deus Ex series
Fantastic series. Deus Ex 1 is so nostalgic but it simply was an amazing game back in the day and it still is. DE2 may be hated by some but I enjoyed myself with that one aswell. Human Revolution and Mankind Divided..... what can I say... simply fantastic.

Dragon Age Origins & Inquisition
Dragon Age Origins was a great RPG. I've played the demo of DA2 but felt like it wasn't for me. DA3:Inquisition was a fun experience and I've not played The Veilguard and I doubt I ever will. Bioware used to be my favourite developer, now they are one of my least.

Fallout 1, 2, Tactics, 3, New Vegas, 4.
Fallout 1 was my first real cRPG experience and I love the genre since then. Fallout 2 expanded on that but both games remain in my top 10 favourite games ever. I even love Fallout Tactics, which is a different type of game. Honestly, not a huge fan of the Bethesda games. Fallout 3 and 4 are fun... but different. Fallout New Vegas however is the game that might even top Fallout 1 and 2 for me.

Half Life 1 & 2
The Half Life games had a huge impact on me. The original game was my first PC game (modern PC game... not counting Commander Keen etc.) but it also changed FPS games as a whole since Half Life came with a real story and it was way different than the other FPS games at that time. Even though I prefer Half Life 1 over 2 , HL2 surely was a game that came with so many new technical advancements and as a whole still remains as one of the best FPS games of all time.

Knights Of The Old Republic 1 & 2
Perhaps technically not the best games but I adored both these games. Great story and it made me love Star Wars more.

Little Big Adventure 1 & 2
Probably more nostalgic than a technical masterpiece. Both games were hard to control but the cute graphics and story made up for that. Plus let's not forget the amazing soundtrack.

Mass Effect Trilogy
All three games are simply amazing, hands down the best sci-fi games ever made. I still haven't finished Andromeda since it doesn't come even close to the trilogy.

Mirror's Edge 1 & 2
Mirror's Edge is most likely more a nostalgic trip since those were some good years for me but still both games offer something unique you don't see in (many) other games.

Neverwinter Nights 1 & 2
Honestly, compared to some other RPG's in this list, NWN1 & 2 are not the best but they are still amazing RPG's.

Outcast I guess more nostalgic than anything else. Outcast was unique when I first played it and if I'm not mistaken one of the first open world 3D games with voxel technique. Anyways, great 'Avatar-esque' story.

Planescape Torment
Although at first I didn't like PT since it wasn't "Fallout", I still began to like it since it has a unique world and writing.

Resident Evil series
Ok obviously there are a lot of games here and not all are masterpieces. Big fan of the original trilogy + Code Veronica and RE0. RE4 is a masterpiece, even though at first I did not like the new style. RE5, RE6 were playable but I never could really get into the Revelations 1 & 2. RE7 and RE8 were simply amazing.

Sanitarium
Perhaps not known by many but surely one of the weirdest games I've ever played. Technically not the best game but just a really unique game.

Tomb Raider series
Tomb Raider 1 was my first game on the Playstation and I have remained a fan ever since. The first three games are probably my favourites. Tomb Raider 4 and 5 were fine, we don't talk about TR6.....
Legend, Anniversary, Underworld .... all good games but different. The reboot Tomb Raider, Rise of the Tomb Raider, Shadow of the Tomb Raider are all great games.

The Witcher 1, 2 & 3
Obviously, not much can top The Witcher 3. Hands down one of the best games ever made. Still, some love should go to The Witcher 1 and 2 aswell, great games in their own right.