Over the decades I have seen a lot of fantasy books pointed to as clear influences on HP, and I myself have read a number of fantasy books and thought "This is literally exactly [some aspect of HP] and there is no way this wasn't an influence." But I'm not convinced JKR is well-read enough for as many of these things to be direct influences as we might think. More likely she just culturally osmosed a lot of fantasy tropes and used them without giving a second thought to where they originated or were popularized.