There’s a few, I use Voyager myself on iOS. The only real difference from Lemmy so far that I see on a user side is that you cannot upload images directly into a comment, but that functionality is in the works.

If you want to give it a try, you’re welcome to join my PieFed instance https://quokk.au/. If you have any issues, let me know what app and if it’s ios/android and I’ll see if I can make you a guide.