Defender, flying
{T}: Put Gomazoa and each creature it's blocking on top of their owners' libraries, then those players shuffle.
Gomazoa’s ability can be activated any time its controller has priority. It doesn’t need to be blocking any creatures.
If Gomazoa isn’t blocking a creature at the time its ability resolves, only Gomazoa is put on top of its owner’s library, and only that player shuffles their library.