Paid resource
HSK Books / 发展汉语 (Grammar Focus)
My notes
The grammar coverage is comprehensive but the density of points without enough practice contexts means some things don't consolidate the way they should. You can read a grammar point, understand it, and still forget it a week later if you haven't found a way to actually use it. Pair with a YouTube explanation and your own sentence building to make it stick.
The grammar sections in the HSK books are dense and systematic, which makes them good for initial exposure and bad for consolidation on their own. I developed a habit of copying each grammar pattern into my own notes with three original example sentences rather than just the ones from the book, which forced me to actually use the pattern rather than recognise it. The points I struggled with despite multiple review sessions were the ones I'd look up on Say Nihao to get a different framing — the book and the video channel together covered what neither did alone.