Have fun 🙂
http://www.esl-lounge.com/student/grammar/4g68-used-to-be-used-to.php
http://www.myenglishpages.com/site_php_files/grammar-exercise-used-to.php
https://www.usingenglish.com/quizzes/326.html
https://www.usingenglish.com/quizzes/115.html
http://baladre.info/english/sedaviwebfront/usedto.htm
http://baladre.info/english/sedaviwebfront/usedto3.htm
http://www.perfect-english-grammar.com/used-to-exercise-3.html
http://www.englishexercises.org/makeagame/viewgame.asp?id=2447
http://esldivlabs.vcc.ca/ELSA/Instructor_Web_Exercises/Grammar/Used_to_Cloze.htm
http://www.english-area.com/paginas/usedtoortobeusedto.htm
https://www.5percangol.hu/nyelvtan_feladatok/used-to-get-used-to-and-be-used-to
if you are fed up with grammar, do these:
http://www.proprofs.com/quiz-school/quizshowall.php?title=cae-word-formation-1-forming-nouns
http://www.proprofs.com/quiz-school/story.php?title=fce-exam-practice-use-english-word-formation
http://www.proprofs.com/quiz-school/quizshowall.php?title=fce-uoe-part-3-word-formation