No phone apps that I know of for Koha. I think it works fine on any mobile browser, though. If you know HTML, CSS, or even JavaScript you can do a ton of cool stuff on your library’s catalogue. As for FOLIO, no idea, but I don’t think any exist.
There is VideLibri but it doesn’t add any functionality you don’t already have when accessing the online catalogue of any library on your browser, so I don’t think it’s worth it. Something like the Web Opac App, which let’s you browse a ton of libraries’ catalogues in one app would be a more interesting solution. Unfortunately, it’s stopped being maintained a while ago and went closed-source, from what I can gather.
Off the top of my head, for Berlin International Film Festival, there’s the Golden Bear.