1990-1993 to me were GURPS and GURPS only. I ran a campaign in the classic Lost World/Savage Empire setting. A second one in a Cyberpunk-Horror setting (one of the most vivid and creative RPG experiences ever) and a third one who managed to be a mix between Star Wars, Mobile Suit Gundam, Captain Harlock and Traveller.
After 1993 I stopped playing RPGs and, TBH, I thought that my life was past them. I bought and collected a lot of books... CoC, of course, Cyberpunk 2020, Rifts, WoD (exp. Mage and Wraith), more GURPS and some D&D/AD&D 2E classics. By then my comic-book writing career had taken off (even if it was never the only thing I did) so I welcomed the suggestions (I considered "writing" as creating an adventure and then playing it in my mind with the characters...), but I didn't play RPGs again until 1999.
On that year there was a perfect storm of my colleagues wanting to try them, Planescape grabbing my attention and Planescape: Torment re-igniting my RPG creativity. We started with Star Wars D6, then a couple of adventures at CoC, and then, on Fall 1999, I launched the AD&D/D&D 3.5 campaign that was my main RPG commitment for the following 13 years...