I heard once that the poskim permit "gram mav'ir" on yom tov l'tzrich gadol. For example if someone wants to use a platta (hot plate) that they forgot to plug in they may plug it in with a Shabbos clock that will later turn on the hot plate. Where does it say that gram mav'ir is permitted on yom tov? Who were/are the poskim that discuss this?
Nitey Gavriel (Hilchos Yom Tov Cheleck Aleph, end of Chapter 20) quotes many poskim permitting "gram m'avir" on Yom Tov; see footnote 42 there.