I created list of directories (1000) to create free backlinks
Handpicked directory list, but Indie Hackers, BetaList, and manual searching already solve this.

Vaporware check filters out landing-page-only startups from the S tier.
VCs, startup observers, YC applicants
Crunchbase · PitchBook · Signal NFX
S tier is almost empty. A lot of the "hot" companies didn't survive the vaporware check.
Handpicked directory list, but Indie Hackers, BetaList, and manual searching already solve this.
Custom GPT wrapper that generates investment memos and ranks dealflow for angel investors.
Ahrefs API wrapped in a retro leaderboard — TrustMRR but for domain rating.
Using Stripe Checkout traffic as a proxy for real paying customers is a sharp, data-driven angle — the site surfaces Stripe visits, month-over-month change, share and ARR estimates across categories. Nice UI with filterable cards and clear badges, but the value is limited by scope: methodology transparency and Stripe-only coverage (no PayPal, Paddle, in-app purchases, or enterprise billing) need calling out before you trust it as a definitive ranking.
Typeform clone with AI analysis when SurveyMonkey and Tally already do this.
Community-ranked free LLM fallback list beats OpenRouter's default, but solves a temporary problem.