Bedrock Edition:Item Transmutation
Item transmutation is a glitch/bug that allowed certain items to be converted into other items.
Furnace Fuel Transmutation
This method is not particularly powerful on its own, but is theoretically useful in converting existing items if certain invalid data values are obtained.
From Pocket Edition v0.3.2 alpha to v0.7.6 alpha, a bug existed where items of the same numeric ID but differing metadata could be added to a furnace fuel slot, converting the input item to the item already there. This could be used to convert between the three types of logs, or coal and charcoal.
Bow Transmutation
From Pocket Edition v0.4.0 alpha to v0.10.5 alpha, another mechanic (which may have been exclusive to Creative mode, though this requires further testing) allowed for converting any item with numerical metadata to that same item with metadata 0. This was done by drawing back a bow and immediately switching to the target item after the bow was released, causing the target item’s data value to revert to 0. At the time, this was the only way to obtain ink sacs, apart from using an inventory editor, and it could also convert spawn eggs into a spawn egg labelled 'Spawn .name<'.[1]
Furnace Output Transmutation
(unknown; allows for DV 32767 items)