Youtubers:

Korean Replays *helpful for learning specific champions and matchups, also watching KR pros play. LS *insightful coach and LCK caster, he talks a lot about decision making and mindset. Watch his coaching sessions and his stream. n3ac3y *good coaching videos also nice commentary. Phy and Phy Games *helpful videos and he uploads commentary games from his smurf. unswlolsoc *educational, helpful for grasping concepts.

Streamers:

imaqtpie *less serious but pretty good adc. LS *LS' twitch stream. Doublelift *mechanical adc. Krepo *he plays support, he knows how a lane should be played and talks about what his adc could have done sometimes C9 Sneaky *again less serious but pretty good current pro adc. Valkrin *educational but he mostly plays jungle. still very good especially if you play jungle as a secondary or want to focus on learning general concepts.