that got me thinking, what if there was a breakable barrier block, that can be generated by pokemon like mr mime as a move skill? it could be tied to moves like light screen, and be used in your own bases, without having to use creative mode. the durability of these blocks, could be tied to the pokemons level, ranging from the equivalent of glass, to obsidian. (or just glass, maybe an option to allow server owners to regulate the maximum durabilty)
another move skill could be foresight, to reveal invisible blocks.