Since launching in 2014, Misa has built up one of the biggest, most comprehensive, and most well-regarded Japanese language-learning channels on YouTube. Starting with a "Japanese Lessons for Absolute Beginners" video course series, Misa's channel has blossomed into one of the most in-depth references for English-language mediated Japanese instructional content.
Beyond that initial series, Misa has expanded into a wide range of of videos, covering topics in Japanese such as in-depth guides to specific particles, slang terms like やばい, commonly confused components such as the usage of に vs で and more.
What sets Misa apart is the nuance and depth she's willing to put into her videos. There's of course the forty-minute video on some of the differences between the usage of は vs が, a two-part series on the explanatory use of the の particle totaling nearly an hour and a half, and two videos on causative form totaling just over an hour, among others. Other Japanese learning YouTube videos, especially those in English, tend to go much shorter, covering primarily the surface-level knowledge and leaving the nuance for monolingual Japanese sources, or for a learner to discover on their own through acquisition.
But through Japanese Ammo with Misa, that level of understanding becomes accessible to a much wider range of people.
Really, the only flaw with Japanese Ammo with Misa is the organization. Since releasing "Japanese Lessons for Absolute Beginners," Misa has rarely put together a similarly comprehensive course, or otherwise organized their videos into series or categorizing videos that cover similar topics. But the videos that are there form an extremely thorough foundation of Japanese grammar that can take you pretty far. I'd recommend you either go through videos in reverse-chronological order, skipping anything that doesn't seem relevant, or simply watch the videos on topics you'd like to learn. You surely won't be disappointed!