My great old ones are from 1977, so they'll turn 40 next year.* My first set was opaque purple with the waxed in numbers for showing high/low in the d20. I also have some other opaque d20 from other games I bought.
Of course, there's the guy with the ENWorld Dice Q&A thread who has things like Roman dice, so...
* Note: I didn't include the even older 6 siders from traditional family boardgames that I still have.