Tiny frog that jumped across my path and hid in leaf litter.
It could be several Platymantis species that I have since researched but the colouration didn't match any photos that I found online. Its size and shape also look very similar to a Leptolalax species that I am more familiar with.
Thanks to Arvin Diesmos of Philippine herpwatch.org who identified it as P. corrugatus.