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