Hi and welcome,
It depends on what you like but piefed has today a random button where you can hammer to find your favorite community. (If your piefed instance doesn't have it yet, It will come with the upcoming release)
Hamburger menu > bottom right > random communities :
https://piefed.social/r/random
And lastly there are feeds where you can explore communities by theme, thank to @Skavau@piefed.social :3
I like !superbowl@lemmy.world and this feed https://piefed.social/f/animals
And for cool pics, there is !photography@piefed.social