NotificationX might be a bit more popular than Proof. We know about 1 link to it since March 2021 and only 1 link to Proof. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
I've used https://useproof.com/ before, and it worked really well, and increased conversions about 8%. Source: about 2 years ago
This plugin. https://notificationx.com/ however never used it. Source: about 3 years ago
Fomo - Fomo turns your site into the online equivalent of a busy store
Nudgify - Nudgify is a Social Proof App that includes FOMO, Urgency and Review Nudges. Adding Social Proof notifications to your site helps you build trust and increase conversions on Shopify, Wordpress or any other platform.
ProofGain - Supercharge your conversions with a simple social proof tool
Picreel - Recover abandoning visitors and turn them into customers
SocialProofy.io - Social Proofy is a marketing platform that applies the psychological concept called social proof to help businesses.
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.