DEFINING RELATIVE CLAUSES:
https://www.perfect-english-grammar.com/relative-clauses-exercise-1.html
https://www.perfect-english-grammar.com/relative-clauses-exercise-2.html
https://www.perfect-english-grammar.com/relative-clauses-exercise-3.html
https://www.perfect-english-grammar.com/relative-clauses-exercise-4.html
NON-DEFINING RELATIVE CLAUSES:
https://www.englishexercises.org/makeagame/viewgame.asp?id=4219
https://elt.oup.com/student/solutions/int/grammar/grammar_03_022e?cc=global&selLanguage=en