It depends. FB auth might not be appropriate for B2B and github login wouldn't be appropriate for a non-dev user base. My guess is that you need to think abou

It depends. FB auth might not be appropriate for B2B and github login wouldn't be appropriate for a non-dev user base. My guess is that you need to think about your users. Who are they? Why are they using your app? Your goal here is to reduce friction and you can only do that by offering options specifically selected for your users. As an actionable, go find someone who you expect would find your app useful, ask them. Find your competitors and see what they're doing - even better if you find something missing.