Blockbench, 3D-Coat, 3D Pixel Artist, VoxelShop, VoxEdit, Marmoset Hexels 3, MagicaVoxel, Avoyd, Kv6ToSchematic, Acropora, Qubicle Voxel Editor, 3D Slash, VoxelMaker, Voxel Builder, Goxel, SpriteStack, Slab.js, Voxelator, Project Vox, SpritePile, Curious Blocks, Slab6 are some alternatives to Cubik Studio.