I designed some small hooks for the Suncast shed (small holes displayed in 2nd pic), the one I have is the BMS7780 - 7'x7'. They work perfectly for small non-heavy items, as you can see in the pics I hung a Webber grill and grill tweezers. 

They fit in the small holes that have no thread, made 2 options, 

Option 1: Made for imperfect wholes that have some bur on them (Shed hook) 

Option 2: Made for smooth-cut wholes, this one can hold a bit more weight (Shed hook - extra support)
 

I printed mine with normal PLA (ELEGOO & Handini)