Slack Overflow - A programmer's best friend, now in Slack.
Dr.Explain - Dr.Explain software is a help file authoring tool.
GitCommands - An interactive reference tool for Git commands
HelpSmith - HelpSmith is a help authoring tool to create CHM HTML help files, manuals, and PDF documents.
GitHub + Slack Integration - Full visibility into your GitHub projects right inside Slack
MadCap Flare - Documentation for Any Audience, Language or Format