Regex101.com
JavaScript
regex101 is great for building up regex expressions
weve also got a regex community in the instance at !regex@programming.dev with some stuff in it
https://regexlearn.com/ is interactive to get you started.
Then try reading maybe the python regex docs for more detailed info. There are multiple flavors of regex as well, which makes it even more confusing (yay), but you'll eventually grok it enough to make it a part of your toolbox! I use simple regex frequently for search/replace (VScode or vim), and in the shell.
For more complex string parsing operations, there's often a faster/better method than regex, but it's really good to know.
This isnt really a resource as such, but an interesting game that effectively nerdsniped my whole team:
I just discovered that Exercism.org doesn't have a regex track...
Well, I'll be...
: )
If you like videos then I think this video is quite decent: https://youtu.be/rhzKDrUiJVk?si=UUfyL5ua7FGnGJsL