Answer 1

from newly tags to deprecated tags, sort by category

https://www.w3schools.com/tags/ref_byfunc.asp

Answer 2

i dont know, maybe more than 200 tag

Answer 3

https://code.sololearn.com/Wc8Dz2ZjWn9N/?ref=app

Answer 4

Only the important tags (no html5 tags):

http://webdesignfromscratch.com/html-css/html-tags/

Answer 5

Go to the main page's course
Go to CHANGE
Go to HTML
Go to Options (three dots)
Go to Glossary

There are all tags used in the course and a brief description.