There are tonnes of resources you can use to sharpen your skills or learn new stuff. Some of the ones I'm using now, or have recently used are listed below.
- Substack wizardly training
- Hired in tech
- Learn x in y minutes
- Codewars is great way to exercise your brain using their Katas. There are tonnes of languages to choose from too.
- Khan Academy really needs no introduction.
- Devchat contains lots of great podcasts of various technologies.
- ryanstutorials.net has Bash, Linux and many other well written tutorials.
- Python from scratch looks really good.
- Various resources from Assembly language to programming in Java
Cracking the coding interview
Hired in tech has some awesome resources for algorithms, white boarding, and more.
Frontend masters has some seriously cool training resources. Especially the one week course:
- Mozilla html tutorial