So, I was also recently dabbling quite a bit in the x86 assembly side of things. Though right now I have only really worked in with the basic instruction sets, I have mostly been able to self-teach myself a lot of the works.
There is online a nice YouTube playlist done by OpenSecurityTraining.info which outlines the basics of x86 assembly. This I have found alongside the wikibooks to be quite a useful set of references to learn x86 assembly.
I have also thought of making something based off TIS-100 in unity that could be used as an educational game to help supplement teaching and hand-writing assembly code itself, though as I only know small parts of assembly, it will definitely be a work in progress, and a nichè within itself though I don’t know how successful it may be, even if I manage to finish it.