All of these are pretty long and have action and/or magic (⌒▽⌒)
http://www.mangago.me/read-manga/gosu_the_master/
http://www.mangago.me/read-manga/angel_densetsu/
http://www.mangago.me/read-manga/the_legendary_moonlight_sculptor/
http://www.mangago.me/read-manga/saver/
http://www.mangago.me/read-manga/lookism/
http://www.mangago.me/read-manga/bremen/
http://www.mangago.me/read-manga/shut_hell/
http://www.mangago.me/read-manga/parasite/
http://www.mangago.me/read-manga/dendrobates/
http://www.mangago.me/read-manga/tokyo_ghoul/
http://www.mangago.me/read-manga/super_outcast/
(that last one has 40 ep currently)
Oh also, here's some sports ones that are pretty long and interesting too.
http://www.mangago.me/read-manga/yowamushi_pedal/
http://www.mangago.me/read-manga/diamond_no_ace/
http://www.mangago.me/read-manga/eyeshield_21/
http://www.mangago.me/read-manga/rookies/
http://www.mangago.me/read-manga/girls_of_the_wild_s/
http://www.mangago.me/read-manga/dance_subaru/
http://www.mangago.me/read-manga/prince_of_tennis/

Looking for something epic to read, action / fantasy / magic prefered, at least over 50+ chapters, like black haze, black clover, silver diamond, ao no ex, tales of demons and gods..
+ if its your favourite & shorter but complete, even underrated here i take it too :D