I’ve posted before about my absolute love of Atom.  I recently was doing a lot of CloudFormation work and just started using atom-cform, a CloudFormation syntax completion plugin for Atom written by Diego Magalhães. It works great and is a port of the popular CForm package in Sublime Text, which I have missed since jumping ship from Sublime to Atom a little over a year ago. It provides real-time context-sensitive CF template scaffolding for everything from parameters to resources:

Another super-helpful CloudFormation plugin for Atom that does both CloudFormation stack validation and launching is Cory Forsythe’s atom-cfn. You have to have a working AWS configuration (the author recommends a working awscli install which is what I have) in place for both validation and launching as it hits the API in AWS. Simply bring up the command palette in Atom (Shift-Cmd-P on macOS) and select either “Cloudformation: Validate” or “Cloudformation:Launch Stack”. Key-bind those commands for added efficiency.