Indie Makers publishes a catalog of startups and software that founders can still join.
Directories with a public submission form
These sites take a URL through a form rather than a public profile or a guest article.
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bestaibrands.com publishes a catalog of startups and software that founders can still join.
birdeye.com publishes a catalog of startups and software that founders can still join.
Bootstrapped publishes a catalog of startups and software that founders can still join.
brightlocal.com publishes a catalog of startups and software that founders can still join.
builtbyme.io publishes a catalog of startups and software that founders can still join.
Code publishes a catalog of startups and software that founders can still join.
connectively.us publishes a catalog of startups and software that founders can still join.
Build with ❤️ Anything publishes a catalog of startups and software that founders can still join.
Marketing for Developers - Justin Jackson publishes a catalog of startups and software that founders can still join.
Doing Content Right - Steph Smith publishes a catalog of startups and software that founders can still join.
dzone.com publishes a catalog of startups and software that founders can still join.
Visit → publishes a catalog of startups and software that founders can still join.
fatjoe.com publishes a catalog of startups and software that founders can still join.
featured.com publishes a catalog of startups and software that founders can still join.
FeedMyApp publishes a catalog of startups and software that founders can still join.
Feishu publishes a catalog of startups and software that founders can still join.
fiverr.com publishes a catalog of startups and software that founders can still join.
Visit → publishes a catalog of startups and software that founders can still join.
Freeble DA: 17 publishes a catalog of startups and software that founders can still join.
The $150M secret - Guillaume Moubeche publishes a catalog of startups and software that founders can still join.
LET US SUBMIT FOR YOUR - $89 publishes a catalog of startups and software that founders can still join.
Hackmd publishes a catalog of startups and software that founders can still join.
Hiten Shah publishes a catalog of startups and software that founders can still join.
When a submission form is the right door
A form is the usual path for product directories: you send a URL, a short description, and often a logo. Approval is not automatic, and the link can be dofollow or nofollow.