Komplete's "Session Strings" is what I often find people using

8dio and LA Scoring Strings. Pricy but you get what you pay for.

Cinematic Strings, Berlin Strings, LA Scoring Strings are all nice choices. I can't speak from experience about 8dios but apparently they're also very popular.

I've been looking everywhere for a plugin that has huge, vast sounding strings, but I'm never 100% sold on anything. What are your guys' go to string plugins?

Check out the various Kontakt libraries made by Native Instruments or what I use, Spectrasonics Omnisphere.

Komplete's "Session Strings" is what I often find people using

+1. if you're looking for even better, their new Symphony series string ensemble and horns make me cry with how good they are.

If you're on a budget, try Miroslav Philharmonik. They hold sales pretty often, I picked it up for $60, but it's a whole orchestral suite, with strings, winds, choirs, piano, and more, with different articulations and individual instruments.