If you use a tool that is not currently supported by Cloudflare's Webhook Notification System, you can use Cloudflare Worker's in combination with a generic webhook to support pretty much any tool on the planet.
This repo contains an example of how to transform the generic webhook response so that it can be delivered to rocket Chat. The entirety of the codebase is 60 lines long and heavily commented.
Check out index.js to get started.
The general principle behind making this work is to transform the generic webhook response into the one
your service of choice expects. In this repo you can see in sample-data.json what a Cloudflare Generic Webhook Response
looks like. You can also see in rocket-chat.json what our target payload looks like. It is simply an exercise of transforming
one to the other and passing it on.