What FOMO/conversions features and integrations would you want?

Social proof and FOMO builds trust, increases conversions, and a host of other things. A latest Indie Hacker newsletter shared that sales page conversions increase by as much as 34% with testimonials. Real time purchases and signups pop can help increase conversions. If someone was building widgets that show FOMO and social proof based on their products, orders and signups data, what features and integrations would you ask for?