How many characters in Dragon Ball can fire Kienzan-like discs? So far I remember 6 characters in Dragon Ball firing Kienzan-like discs. Who are all the characters who can fire them?
Based on the Dragon Ball Wikia, these characters have used this or similar technique:


Krillin
Vegeta
Frieza
Amond (Dragon Ball Z: The Tree of Might)
Goku
Cell
Cell Juniors
Android 18
Baby Vegeta (Dragon Ball GT)
Super Buu (The result of Evil Buu eating Good Buu in a chocolate form)
Master Roshi (Dragon Ball Z: Atsumare! Gokū Wārudo)
Future Warrior (Dragon Ball Xenoverse Game)