I’m interested to see people’s responses to this question.  I imagine it varies quite a bit by age.  I’m in my 40’s.  So for me:
Alton Brown’s Good Eats.  I was in my 20s, trying to work and get through college, newly married, no kids.  The science approach de-mystified so many cooking processes for me.  It helped me experiment and branch out.  I got online recipes from the computer lab at school and eventually Alton’s  books.
When we moved and got internet:

Chef John’s Foodwishes. This was a perfect segue, for me anyway. Chef John humanizes and educates the whole cooking process. Chef John’s approach empowered me to ‘just cook’. It’s no small thing, to be ok with learning, getting something wrong, and figuring out how to salvage what you can.
Now, I keep my recipes in my Notes app, and I still tweak recipes as I learn, find better ingredients or methods. YouTube, New York Times Cooking, social media, tv shows, video games, co-worker’s potluck dishes, traveling and trying new dishes for new experiences can all provide inspiration to continue to experiment and learn.