Flash Gordon Filmation
and He-Man filmationThundercats
Transformers first two seasons and the movie only.
I agree on Thundercats and Transformers being awesome, they have aged surprisingly well. But pretty much everything that Filmation produced back then is an absolute abomination. Watching even short clips from He-Man makes me want to off myself.
In terms of 80s animated series, though, the best was clearly on the Japanese side. Macross/Robotech, Gundam, Urusei Yatsura, Dirty Pair, I could go on. Back then, anime was actually intended for normal people, not weirdo fetishists who have never seen sunlight in years.