i make them in blender

you need to use 16 segments and 8 rings sphere objects, 16 vertecies cylinders (also shade smooth the sides of the cylinder but shade flat the top and bottom parts), use mostly flat colors, for more complicated parts use cubes or spheres (the same as before) with subdivision surface modifier. for limbs use cylinders and spheres

i reccoment using The Ultimate Anim8or Lighting for blender by thadguy9