nice

especially @Cyangmou's rigorous tutorial efforts
I was going to put together some reference sheets for dimetric and trimetric ISO approaches, principles and practices.
have this at the moment and put this together to help a friend might as well post it here, more of a rough guideline to 2 major methods of Isometric construction one being an offset style system where you have alternating offset rows.
I'm more used to using offsets personally. but I know alot of people are far more comfortable with tiles, you just end up with a bigger tileset and more to and fro'ing with different tiles.
I can elaborate on the meaning of this diagrammatic if anyone asks but should be self explanatory. and this one is dimetric 2pixel step (26.565°) which is most common, and I'll probably add another for trimetric later, Fallout 1&2 have the most notable usage of trimetric projection.

also it should be noted there is no real universal approach to isometry only things that have been proven to work and not work and more efficient ways of doing it, I think there was an interview I read online some time ago from they guys who did the original X-Com about their approach and how they overcame some problems with isometric (it was offset, also it gets more complicated when you do multiple floors etc) if I manage to find it, I'll link it here.