There is really only two things that have a high current connection to the battery that wouldn't otherwise blow a fuse, the alternator and starter. Worth disconnecting each in turn and testing them + see if the vehicle's electrics come alive without them connected.
Or you have a faulty battery, that has failed in quite a catastrophic way - do you have another one you can use, or charge up the one you have and have it load tested (not connected to the vehicle).