I know these hooks are only a Euro per three hooks at the Swedish furniture store, but it isn't open on Sunday evenings when I usually reorganize our stuff.
They're easy to print with no supports.
I'm printing them on their side (see picture) with only shells, which makes them durable enough to hold our kids' kindergarten backpack.
Let me know if you like them and post a make!
The author hasn't provided the model origin yet.