The Resonator is the algoritm I use most by far on the H9. Used to be Blackhole, but since that’s featured as a plug-in, I load it in my DAW instead.
It can really make wonders with quite mundane synth sounds – a simple 303 or SH101 pattern turns into shiny, glittering cascades, each turn of any of the knobs on the 303 sounds like you just brought yet another synth into the mix.
I really think Eventide should consider Resonator for its next plug-in with stompbox origin.