They've given us King Shark, Gorilla Grodd, and a lot of fights on Legends with characters like The Atom, Firestorm, and Heat Wave all using their powers.
The Expanse has given us some pretty impressive effect sequences with the Protomolecule.
Once Upon a Time has given us dragons, Ogres, fairies, magic spells, and completely CGI environments.
Those shows have all pulled off some pretty awesome effect sequences on basic cable and network budgets, and I'm pretty sure Netflix is probably going to give A:TLA an even bigger than most of them have.
At this point I've pretty much stopped doubting what they'll be able to do on TV/streaming.