Of course there are other pairings. There are loads of pairings and combinations if you put your mind to it! As for what is canon, however, the ones established by the show itself are Buzz/Ozma, Mira/Romac, and XR/42. You could probably push it a little and say one-sided Booster/Petra, too. As for romances within Team Lightyear, there are none officially (unless you count XR/42), but I know a lot of people like Buzz/Mira. I am personally quite fond of Mira/Romac and find it strange when people pair NOS-4-A2 up with organics when he hates them so much...
IluvCartoons, the bounty hunter's name was Romac and he appeared in "Star Crossed". Very good episode!
Jgirlpopush, Ozma Furbanna is one of the most honoured animal research scientists who took residence upon Karn to study its wildlife. She appeared in the episodes "The Beasts of Karn", "Return to Karn" and "Millennial Bugs".
Shadegriver, Ozma wasn't in "A Zoo Out There". That was the episode with the Chlorm kidnapping senators. Also, her name is Ozma, not "Omar", and Petra is officially with Plasma Boy; I don't think it'd be fair to Plasma Boy if Petra were to drop him for Booster. AndI don't think the producers/writers stopped Buzz and Ozma kissing in "Return to Karn" because they did not like the pairing; Buzz and Ozma officially kiss at the end of "Millennial Bugs" after all, and if the producers/writers didn't like what they were doing, why would they write it in the first place?