GitHub Pages - A free, static web host for open-source projects on GitHub
Webhook.site - Instantly generate a free, unique URL and email address to test, inspect, and automate (with a visual workflow editor and scripts) incoming HTTP requests and emails.
Netlify - Build, deploy and host your static site or app with a drag and drop interface and automatic delpoys from GitHub or Bitbucket
Hookdeck - Hookdeck makes it simple to build and deploy reliable, testable, and debuggable applications that rely on webhooks.
surge.sh - Static website hosting for front-end developers.
Svix - The enterprise ready webhooks service, open-source and in the cloud.