Wow... DOMINATION, the only real ones I can think of at the moment is where my team did about 80% on the opposing team, then again there was only two people on that team.
I was once in a 4v1 match during Splatfest and the other person either disconnected or just gave up because it was something like 98% to 0.something% haha. I feel sorry for that person, or anyone on the unfair side of lower numbers.
I had a match in Camp Triggerfish where my team annihilated the other lol. We made it to their spawn point and held them there where they couldn't get out. I had a splash wall and kept using that to protect us while everyone else shooters at them. They had to come off their spawn pad to shoot at us where they were vulnerable and my team picked them off. They couldn't even get off the side paths haha.
Closer to the end, one of them got a Kraken and broke free a little so we only covered around 80-85% of the map but otherwise it would have been in the 90s.