Initiative is 1 - 10 so ... 1D10, discard duplicate results.
How would this work. Player A rolls a d10 and scores an 8. Then Player B gets a 6 and Player C gets an 8. Does C re-roll until they don't get a 6 or 8? And then the next entity rolls?
If you would deal cards, you have to deal the cards one at the time, meaning that Player B can't get an 8 because Player A already got that card and Player C can't get card 6 or 8. The same can be done with dice. Player B have to re-roll if he happens to roll an 8 just because Player A already got that and Player C have to re-roll his dice if he get a 6 or an 8.