Pronouns

explanation:
http://www.englisch-hilfen.de/en/grammar_list/pronomen.htm
http://www.ego4u.com/en/cram-up/grammar/pronouns
http://learnenglish.britishcouncil.org/en/english-grammar/possessives/possessives-pronouns

exercises:
http://www.englisch-hilfen.de/en/exercises_list/pronomen.htm
http://grammar.ccc.commnet.edu/grammar/cgi-shl/quiz.pl/pronouns_add2.htm
http://www.myenglishpages.com/site_php_files/grammar-exercise-personal-pronouns.php#.UnkHOxBHLTI

possessive pronouns (mine, yours...):
http://www.englishexercises.org/makeagame/viewgame.asp?id=5173
http://www.myenglishpages.com/site_php_files/grammar-exercise-possessive-pronouns.php#.UnkH1hBHLTI
http://www.learnenglishfeelgood.com/esl-possessive-pronouns2.html
http://www.ego4u.com/en/cram-up/grammar/pronouns/exercises?04
http://a4esl.org/q/h/vc-pronouns-lb.html
https://english.lingolia.com/en/grammar/pronouns/possessives/exercises/articles/exercise-on-possessive-pronouns

object pronouns:
http://a4esl.org/q/h/9901/jd-pronouns.html
http://www.ego4u.com/en/cram-up/grammar/pronouns/exercises?02
http://members.iinet.net.au/~adelegc/grammar/object_pronouns/objectpronouns.html
http://www.eflnet.com/tutorials/subobjpronouns.php
http://www.englisch-hilfen.de/en/exercises/pronouns/personal_pronouns3.htm
http://www.1-language.com/englishcourse/unit8_grammar_exs2.htm
http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-13991.php
http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-13991.php
http://www.englishexercises.org/makeagame/viewgame.asp?id=1965