jonas schedman suggesions----
For checking good websites designs suggested by jonas schedman
1)https://land-book.com/
2)https://onepagelove.com/
3) https://www.awwwards.com/
4) https://www.appsignal.com/


Useful websites 
1) Base64decode.org 
2) caniuse.com to check browser features compatibility 
3) visualgo.net for learning DSA 
4) cs.usfca.edu for DSA 
5) https://latentflip.com/ - checking nodejs
6) https://explainshell.com/ -for CLI commands explanation 
7) latentflip.com - for js code execution visualization 
8) jsv9000.app - JS code execution visualization 
9) regexr.com regex practice and visualize
10) algomap.io learn algorithms 

Other websites
Bbox.com for getting lat long
Geojson.io for checking geojson
https://100dayscss.com