List of free clean-code stuff for developerππ½
If you're looking for all programming tools around clean-code (not just free). Check this page List of clean-code Programming Tools

Viezly
Viezly helps you review code easier with enhanced navigation and review helpers
Tag: code-review, clean-code, diagram
Free for open source repositories Free for personal usage

DeepSource
DeepSource helps you write clean code on every pull-request. Built for teams who move fast and donβt break things.
Tag: code-review, clean-code
Unlimited public repositories Unlimited lines of code analyzed Unlimited private repositories for individual accounts 1 private repository for teams/organizations Continuous analysis with GitHub, GitLab, and Bitbucket 3 team members

SonarCloud
Enhance your workflow with continuous code quality, SonarCloud automatically analyzes and decorates pull requests on GitHub, Bitbucket, Azure DevOps and GitLab on major languages.
Tag: clean-code, security, code-review
Free for public projects Unlimited lines of code Anyone can see your project and browse your code You have access to the full SonarCloud feature set Choose members of your team who can work on your projects