All episodes have been uploaded by Treehouse Official
From The Lost Media Wiki
As of July 17, 2020, Treehouse Official uploaded the entire Seven Little Monsters series to Youtube (albeit the first 13 episodes are for some reason unavailable in the US). I'd update the article myself, but I can see it needs to be reorganized anyway...
here's the playlist link: https://www.youtube.com/playlist?list=PLUIixndCOJ8x1w8u1eBROiQEUfAzvRv2C