Which one do you like?

[Tank]

Do you have a favourite religion? Real or not. If so, why so?

[billy rubin]

mine.

i am an ordained priest in the universal life church.

i have a certificate.

i think i was drinking when i applied, tho, as i mispelled my name

[zorkan]

I am the high priest of Zorkanism, the supreme religion of the galaxy.
It is my duty to introduce it to the world.
At present It's only me, but with repeated doublings it will become global.

[Icarus]

My favorite religion is; None.  It is becoming more and more popular these days.

[Asmodean]

The Asmo is the God of Grumpiness-among-other-things. He doesn't even like His own Divine Religion.

Of the existing or historical ones..? Hmm... ancient Shinto, perhaps? At least, I think it would have to be something in that general avenue-ish.

I think a religion that sells "nothing" is a big ask, so as close as you get. You may "need" to appease the rock spirit to have your cave not collapse on you, but it will bring you neither lands (or other riches) nor enilightenment, nor promise to preserve your consciousness after you hit the proverbial bucket. That sounds benign enough, though I'd still be peeved by people imbuing "random stuff" with attributes it can and does do without. (As in, in my world view, "your" rock spirit is just a rock)

Yes. A religion of "here's your goat, now kindly leave me alone for another year." Not as dislikable as some others.