How to reinforce outdoor yard shed

Hey folks,

I've recently run some electric to my yard shed, and in doing so, found that the foundation is... Bullshit.

I knocked down the trellis board to do some stuff underneath, and found that the entire building is supported by stacks of cinderblock, many with wood shims. Incredibly half-assed, which I've learned to expect from the house's prior owner. Pictures are here.

How can I support this building better, without pouring a slab? I'm looking for somewhat economical and effective methods, and am curious to know if each answer may or may not pass an inspection if performed.

Any guidance would be greatly appreciated!