Where do you promote iOS apps organically without paid ads?

Paid UA is out of scope for me right now. I am talking pure organic: communities, directories, newsletters, review sites, social, anything that actually moved the needle for you.

What has worked (or clearly not worked) in your experience? Even rough notes help, like which channel, what kind of app, and whether it was a one-off spike or steady traffic. Looking for concrete channels, not growth-hack lists.