This page says about the features that are not added to PE yet, but they are confirmed.
- Rabbits (0.13.0)
- Polar Bear
- Ender Dragon
- Guardian (0.16.0)
- Elder Guardian(0.16.0)
- The Wither(0.16.0)
- Redstone Lamps (0.13.0)
- Iron Doors (0.13.0)
- Tripwire Hooks (0.13.0)
- Daylight Sensors (0.13.0)
- Buttons (0.13.0)
- Pressure Plates (0.13.0)
- Levers (0.13.0)
- Redstone Torches (0.13.0)
- Ender Chests
- Stained Glass
- Redstone Mechanics (0.13.0)
- Placable string (0.13.0)
These are the removed features in Minecraft PE.
- Glowing Obsidian
- Nether Reactor
- Nether Reactor Core Block.
- Cyan Flower
- Camera(0.14.0)(not obtainable through vanilla Creative Inventory.)
- These features may be removed, but can still be obtained through inventory editors, or through the /give command, which is available in the 0.16.0 beta (aka 0.15.90.X) using the following syntax: /give @p camera/nether_reactor_core. "
Secret Features are features that are added to PE, but can only be obtained through inventory editors. These are the secret features in PE.
- Iron Doors (implemented in 0.9.0)
- Ghast Spawn Egg (before 0.12.1)
- Slimeballs (before 0.12.1)
- Saddles (do not have a use yet before 0.15.0)
- Allow and Deny blocks, added in the first beta release of 0.16.0, later removed in the second release. These are features which are currently available on Minecraft Education Edition.
- Iron Doors are currently useless since redstone mechanics aren't added yet.
- In Update 0.13.0, redstone will be placable.
- In 0.14.0 the camera will break the game if it was activated.