There were 20 sided D10s. Those actually came first. It was suggested that you roll a D10 and a D6 together. a 4+ on the D6 indicated that you add 10 to the result of a D20. That was in the mid 70s. The D20 came soon after in the late 70s. I remember using those in highschool. c1979-1983. The actual D10s with only 10 sides came out sometime in the mid 80s…best guess. I remember seeing them for the first time in college. Probably 1984 or 85.
"Nearly all men can stand adversity, but if you want to test a man's character, give him power."