From memory the cards that stood out were

Nvidia 6xxx series, which was the first card to support SLI. I remember my gaming pc in college with 6x series card, and being able to get another card and use and SLI bridge that increased performance in some games.

Nvidia GeForce 900 series, which had the Titan with 12gb, first card iirc to able to support larger resolution gaming.

Nvidia RXT series which started with 20xx i think, first card to come with 24gb of ram.

And then the modern 4xxx series which used to fry power cables.