BIT, CJTT, NASTe seasons 1 and 2, KBooB, and KTiT were pre-UNAC. Well-documented, organized, competitive, and had major players.
https://forums.taleworlds.com/index.php/topic,154586.0.html
https://forums.taleworlds.com/index.php/topic,169650.0.html
https://forums.taleworlds.com/index.php/topic,194970.0.html
https://forums.taleworlds.com/index.php/topic,238001.0.html
https://forums.taleworlds.com/index.php/topic,256866.0.html