I like this Wikipedia page for x86 instructions, because it doesn't just list the instructions -- it also shows the x86 processor in which the instruction first

I like this Wikipedia page for x86 instructions, because it doesn't just list the instructions -- it also shows the x86 processor in which the instruction first appeared. If the listed processor models were released in different past years, some earlier than others, then think of this list as a tool for virtual "time travel" (well, x86 instruction set-wise!)