So peach has a 0-death on seemingly the entire cast. It's a little tricky to do, but there's a much easier version that takes most of the cast to 70 . Throw a turnip down -> footstool, float to cancel the footstool, sourspot nair to regrab turnip -> repeat. Takes about 5 minutes to learn, if that. The "tricky" version isn't much harder, just enough to where someone can't do it after viewing it once -- I was able to do at least one iteration after seeing the nair infinite and once I was able to get 3 in a row I could do as many as the game would allow.
The hard part is for peach to get it started. You have to be standing RIGHT next to them, meaning it only works if Peach has a turnip in her hand and you spot dodge or roll to a vulnerable spot... or have your shield broken or are put to sleep.
Luckily for peach, her toad counter puts you to sleep! The wakeup animation seems to give you enough time to start the infinite at 0%. Peach's toad only puts you to sleep if you are grounded, so the counter to it is "use aerials" or "grab".