These features were once in Minecraft, but were removed.
List of Removed Features
Cyan Flowers were coded in Minecraft Pocket Edition as replacements for the Rose. They were removed in Update 0.9.0 when they were replaced by Poppies.
Cameras were added as a means to take screenshots in-game. They were only accessible through inventory editing and were removed in Update 0.9.0.
It was stated it may be re-added with a proper image sharing system.
Gravel were used as paths on Villages, but in Update 0.11.0, they were replaced by Grass Paths.
The Nether Reactor was replaced by the Nether dimension in Update 0.12.1.
The Stonecutter was removed from Survival Mode in Update 0.13.0, and its functions were moved to the Crafting Table. It can still be found in the Creative Mode inventory.