Some grammar revision sites

B1 level:

All of the Grammar and Vocabulary sections on the left and right of this page:

https://www.english-practice.at/b1/vocabulary/b1-vocabulary-index.htm

This is huge because there are pages inside pages!

B2 level:

https://www.english-practice.at/b2/grammar/prepositions/prep005-prepositions.pdf

https://www.english-practice.at/b2/grammar/connectives/con004-connectives-linking-words.pdf

https://www.english-practice.at/b2/grammar/connectives/con003-connectives-linking-words.pdf

https://www.english-practice.at/b2/grammar/connectives/con002.pdf

https://www.english-practice.at/b2/grammar/prepositions/prep004.pdf

https://www.english-practice.at/b2/grammar/prepositions/prep003.pdf

https://www.english-practice.at/b2/grammar/connectives/con001.pdf

https://www.english-practice.at/b2/grammar/prepositions/prep002-prepositions.pdf

https://www.english-practice.at/b2/grammar/prepositions/prep001-prepositions.pdf

and then ....... as many of the links to Grammar and Vocabulary exercises on the left and right of this page as you want to do:

https://www.english-practice.at/b2/vocabulary/b2-vocabulary-index.htm

This is also huge because there are pages inside pages!

Check also: https://www.english-practice.at/index.htm

in case you missed something

C1 level

https://agendaweb.org/vocabulary/tests-advanced-vocabulary3.html

https://www.examenglish.com/CEFR/C1.htm

https://www.esl-lounge.com/student/advanced.php

https://www.cambridgeenglish.org/exams-and-tests/advanced/preparation/

https://www.flo-joe.co.uk/cae/students/tests/

https://www.englishrevealed.co.uk/cae.php

https://learnenglishteens.britishcouncil.org/skills/listening/advanced-c1-listening