Free
Freecodecamp.org
EdX.org
Courses are free, certificates are paid
Open Classrooms
Every Programmer Should Know - mtdvio
Not a learning site itself but a Github repo with links to a large number of other resources
The Odin Project
Open Source Society University
Harvard Courses Online
Most are through EdX- certificates of completion may not be free
edabit
w3schools.com
The Open Source Computer Science degree
Coursera
Coding Interview University - jwasham
IBM Developer
Programming Notes for Professionals books
Curated List Articles
Paid
Udemy
JetBrains Academy
Pluralsight
egghead.io
Web development focused, but also has AWS