Google Play has many free mods available for "Minecraft Pocket Edition." MCPEuniverse.com also has mods available for Android and iOS users as of June 2015.
Modifications for "Minecraft Pocket Edition" may be buggy and require time to install properly. Mods that are poorly designed sometimes prevent the game from initializing and can corrupt saved game data. Too many mods at one time can also have an adverse effect on saved game data, particularly when multiple mod scripts overwrite each other. Uninstalling a mod is also dangerous since uninstalled mods leave behind orphaned scripts in the saved game files, which can create additional bugs.