Unused circuits in the fuse block

I've tried to search for this a half dozen ways and can't find anything related, so does anyone know if there's a way to utilize the circuits in the factory fuse block (inside the cab) which come from the factory "empty" aside from add-a-circiuts?

I've already got one add-a-fuse in there, and I'm wondering if there's a cleaner way to do some additional wiring work I have coming up (and maybe clean up the one I've got already in the process).

 

I'm looking for the same thing. It's getting cramped with add-a-fuses.

 

I just broke down and got an additional 8 line fuse block to put in the engine bay, I'm rewiring a few things onto relays and putting all the new stuff on relays as well, so I'll probably even be pulling out one of the in line fuses I've got in there (probably leave the one for the horn, that one's been there so long the wires are too grimy to bother consolidating)

 

Sourced fuse block from Amazom. Ran a fused 12ga wire from batt post located under the fuse / power distribution box on the left, to the battery post on the fuse block. You can then source fused 12v power from the fuse block. I have driving lights, underhood lighting and aux hella fogs wired to my fuse block w/ one open power spade left. Could easily be located under the dash.