In my opinion, the FV-1 octave effects aren’t very usable compared to pedals like the EHX Pog and it’s variants. The high octave is especially warbley, and there’s some substantial lag. However, for DIY it’s the only real option so far (unsure if the Daisy seed can do polyphonic octaves).
I like the OC-2 / Ocelot. It’s monophonic, and sometimes glitchy, but it sounds great.
I did a video of all the FV-1 effects awhile back, here’s a sample of the pitch effects. The octave up/octave down part is near the end of this section.