A plugin which will mix a sidechain signal into the current channelstrip and allows delaying the signal and flipping the phase. This was meant as a replacement for an AUX-Send e.g. to add different sources to an reverb bus with different predelays. See the linked Codeberg page for a more detailed explanation.
A siple phase flipper without any GUI
GateIt [LV2, VST2, VST3, CLAP, Jack Standalone]
A gate which is open by default and if triggerd by an threshhold runs through a hold, decay and wait cycle. See linked Codeberg page for a more detailed description