If you're hunting for 'Supergirl', your best bet is probably HBO Max right now—that's where most of the CW shows ended up after the whole streaming shuffle. I binged the whole series there last winter, and the quality was solid. Before that, it was on Netflix for years, which is where I first got hooked! The show's got this perfect mix of superhero action and workplace drama that makes it super bingeable.
Fun side note: If you're into behind-the-scenes stuff, the crossover episodes with 'Arrow' and 'The Flash' are worth checking out too—they’re all over the place streaming-wise, but HBO Max has most of them bundled together. Also, if you’re outside the U.S., platforms like Amazon Prime sometimes have it region-locked, so a VPN might be your hero here.