r/SmallBusiness explicitly does not condone advertising your own products. This is how they describe themselves: This sub is not for advertisements! Questions and answers about starting, owning, and growing a small business only. That said, if you have real questions or are able to provide value, you can probably still find some users or feedback there.

r/SideProject is a subreddit for sharing and receiving constructive feedback on side projects. It has 148k members and is among the top 1% of subreddits by size.