Here's something fun I made in blender. The photograph is of one after a layer of light blue, Rustoleum, textured spray paint.
You will need support material and solid in-fill. I recommend around using Repetier Host with infill contact distance of 0.5mm to 0.6mm. Cura will also work, but the support material is even more difficult to remove.
You will need to pick out A LOT of support material. This step takes me over an hour. Use needle nose pliers or a dental pick with a hook shape. A scratch awl helps too.
Get aggressive with the tools! }:-0
The rounded shape of the model itself tends to deflect the sharp point away, so it resists scratching remarkably well while the sharp point hooks and removes support material. It's designed to flex quite a lot without breaking. It's smaller than my fist, but I can stand on it with one foot no problem.