So many to choose from, but a recent favourite is NewPipe. Nice customizable interface, actively maintained, works reliably except for when YouTube changes things on their end (keeping up in a cat-and-mouse game with YouTube can't be easy!), and has good support for PeerTube too.
Just a few of the essential apps I'd recommend for android. All are open source and free of trackers last time I checked. All but the last two are on the play store. Most of them are better working and more privacy friendly than alternatives.
QOTO: Question Others to Teach Ourselves. A STEM-oriented instance.
An inclusive free speech instance.
All cultures and opinions welcome.
Explicit hate speech and harassment strictly forbidden.
We federate with all servers: we don't block any servers.