Nifty - Manage projects, work, and communications in one place.
Enlight - Performance and Error Monitoring. We keep an eye on your applications and notify you about performance issues and errors.
Intercom on Product Management - The ultimate resource for aspiring product managers
Lambda School - A full Computer Science education - free until you get a job
Party Line - Use Slack to manage your projects
Free Code Camp - Learn to code by helping nonprofits.