There are a lot of great contributors to the Reddit chess community. Recently, I really enjoyed Tony Rotella's analysis of J.Xiong vs. G.Kamsky, US Champs 2016 found here: https://www.youtube.com/watch?v=RnGxP8njaJ0&feature=youtu.be
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Tony Rotella's whole video is instructive because GMs, who obviously know a lot of openings, are able to play "anti-" systems or what could be described as the most critical, most testing, response (yes, I understand this wasn't the particular point he was trying to make, but Tony Rotella's video has some ideas related to Kingscrusher's video on "Why play opening main lines?" found here: https://www.youtube.com/watch?v=6bZRH1aOl4Y)
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Nakamura just gave an interview in the 2016 U.S. Chess Champs where he said something like it's risky for a player to push too hard for the win unless it meets the "demands of the tournament." Both Tony Rotella's recent video and Kingscrusher's video have caused me to look closely at this whole risk vs. reward dynamic evident in a player's choice of chess opening and the issue of if/when should a player deviate from "main lines" which I've noticed is an interesting undercurrent in a lot of chess tournaments.
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Perhaps the single most instructive chess videos I've watched which has helped me improve as a player is Zibbit's (FM Ingvar Johannesson) series on "Pattern Recognition" found here: https://www.youtube.com/user/zibbit/videos
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Side point: John Bartholomew has a good, solid channel. I enjoy the analysis of all his 10 to 15 minute games. ChessExplained also does a really good job. And I enjoy GM Huschenbeth's clear analysis of his over the board games (see here: https://www.youtube.com/watch?v=CIayysrfuEo)."
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Bookmarking for future reference: a thread requesting recommendations of helpful YouTube chess channels/videos found here: https://www.reddit.com/r/chess/comments/3g5b1l/recommend_some_youtube_channels_streamers_to/