Once you find a good author you stick with them, perhaps back then there were less and so they took it upon themselves to create them. My favourite’designer’ book is little blue and little yellow by Leo Leoni (I think), it’s basic colour theory, so simple and easily conveyed.
I’d also recommend anything picture books by Julia Donaldson and Alex Schafer (the Gruffalo). They are great for 2/3+. My child is 11 now and refuses to donate them, she loves them so much.