power:
http://www.mangago.me/read-manga/solo_leveling/
http://www.mangago.me/read-manga/the_legendary_moonlight_sculptor/
http://www.mangago.me/read-manga/the_scholars_reincarnation/
http://www.mangago.me/read-manga/overgeared/
http://www.mangago.me/read-manga/apocalypse_alice/
knowledge:
http://www.mangago.me/read-manga/tales_of_demons_and_gods/
http://www.mangago.me/read-manga/a_returner_s_magic_should_be_special/
http://www.mangago.me/read-manga/tomodachi_game/
http://www.mangago.me/read-manga/ernak/
http://www.mangago.me/read-manga/isekai_yakkyoku/
http://www.mangago.me/read-manga/saving_80_000_gold_coins_in_the_different_world_for_my_old_age/
skill:
http://www.mangago.me/read-manga/saijou_no_meii/
http://www.mangago.me/read-manga/isekai_houtei_rebuttal_barrister/
http://www.mangago.me/read-manga/imperial_guards/
Comments above did well with their list. I just wanted to add on one that's one of my favorite:
http://www.mangago.me/read-manga/black_haze/
manga where MC (preferably male) surprises everyone with his power/skills/knowledge, etc?