Three kinds worth your time
Launch sites (Product Hunt, Hacker News Show HN, Indie Hackers) bring a short burst. Category directories (lists of tools for your niche) bring slow, steady visits from people comparing options. Review and software marketplaces matter more as you grow.
Prepare once
A one-line tagline, a 50-word and a 150-word description, 3-5 real screenshots, a square logo, pricing, and a founder note. Write it from how buyers describe the problem, not your feature list.
Skip paid listing bundles
Services that submit you to hundreds of directories mostly create low-value links. A handful of relevant listings beats hundreds of irrelevant ones.
Track each listing
Use a separate tracking link per directory and check after a month. GTMorganic's Launch kit lists suitable directories with copy from your Product Brain and a tracking link for each. You submit; it never submits for you.