Origin
Ultima™ Underworld 1
https://www.origin.com/usa/en-us/store/ultima/ultima-underworld-the-stygian-abyss

Ultima™ Underworld 2
https://www.origin.com/usa/en-us/store/ultima/ultima-underworld-ii-labyrinth-of-worlds

Syndicate™ (1993)
https://www.origin.com/usa/en-us/store/syndicate/syndicate-1993

GOG
Ultima Underworld 1 + 2, Syndicate Plus (1993) y Syndicate Wars (1996)
https://www.gog.com/promo/rerelease_ultima_underworld_and_syndicate