there are A LOT. Its been a long time since I looked into them so i cant recomend specific ones but just search 'cbr' on the play store. as for comics...umm...i don't know what the rules here are when it comes to talking about that lol
fair enough lol. Honestly i don't know good websites anymore either but for both comics and books i just google 'blah blah blah' PDF and usually find something right away.