Notion
I use Notion basically as my second brain. When I come across an interesting (code related) tweet, see an useful code example or gather new knowdledge through an article I save it to my Notion library. A small insight into what's on my mind.
Tweets
When you're in search for useful tips and tricks, tech Twitter is a perfect source.
Articles
Varying from case studies to tutorials and in depth knowledge.
CodePens/CodeSandboxes
People on the internet build the most incredible things.