On Tap is Carbonated Audio's sidechain ducking plugin. It gives you a classic pump without routing a kick to a compressor: you insert it on a track and pick a shape. The core is a library of 16 hand-crafted ducking curves, including a standard sidechain pump, a dedicated sub-bass duck and a reverse chain, with a slope offset, a shift amount and a draggable end marker to tune the result. Three trigger modes drive it, Sync to DAW tempo, MIDI from any note, and Audio from an incoming signal. The same developer's FOAM ducking reverb bakes that idea into a reverb, so there is nothing to route.
The band-split crossover, from 20 Hz to 5.12 kHz, lets you duck only above or below a frequency, so you can pump the sub out of a kick's way while leaving the top untouched. Anti-click smoothing cleans the gain transitions, and the developer reports zero latency with no lookahead. It is $20, one time, for three machines, with formats VST3, AU and AAX on macOS and VST3 on Windows. The nearest rivals are Kickstart 2, Cableguys VolumeShaper 6 and the ShaperBox 3 bundle, and On Tap undercuts them all. For the same studio's ducking reverb, see FOAM. Full walkthrough in the On Tap first look.