Pedals that stack with the Mooer Twin Tender Octaver Pro

Beetronics Overhive

The transparent tone has headroom to spare — Beetronics Overhive gives it medium gain to fill it with

Beetronics Nectar

Run Beetronics Nectar into that transparent platform and it finally gets some low gain

Neunaber Wet Mono Reverb Pedal

Run Neunaber Wet Mono Reverb Pedal after Mooer Twin Tender Octaver Pro in the signal chain, clear of Mooer Twin Tender Octaver Pro's own gain stage — goes in the amp's FX loop (or last, into a clean amp)

Mr. Black Bloodmoon

Keep Mooer Twin Tender Octaver Pro's octave voice out front: Mr. Black Bloodmoon goes after Mooer Twin Tender Octaver Pro in the signal chain so its dark voice doesn't muddy it — goes in the amp's FX loop (or last, into a clean amp)