Glimmar 64x is the best steampunk texture pack for Minecraft PE. This will change most blocks, mobs and tools including armor and weapons to steampunk theme. Every thing will look like something robotic, even mobs will be robots with guns in their hands.
It is worth paying attention to the huge number of new sounds to fully immerse yourself in the steampunk world, we recommend to include sound in the game. You will have a lot of new tools that can be a great decor for your home. Also, all pets will have the form of steampunk, it's very funny.
I am a professional from Minecraft PE Team that creates and publishes the best content for Minecraft players. We have been studying custom gameplay, modding features, as well as popular game themes for a long time. You can be sure that our materials are designed for the player to spend more time in the game world than usual. Additionally, our modifications will allow you to turn your game into absolutely any other theme. I'm also a pretty good player, so I'll try to answer any of the questions in the comments.