The More Mobs mod adds not-so-original mobs to Minecraft Bedrock Edition. He simply modifies them in the game outwardly, and also slightly changes the characteristics, adds weapons and objects to them. So, a zombie in MCPE will have many variations, including those with textures different from the original.
The More Mobs mod is sure to appeal if you do not want Minecraft Bedrock Edition to resemble a colorful circus due to its abundance. The mod fits perfectly with the already established balance of Minecraft BE, and practically does not change it. But playing becomes much more interesting.