http://pokemondb.net/pokebase/18970/what-is-the-most-optimistic-move-of-each-type which Pokemon has lots of that
This question cannot really be answered,but here are some Pokemon that have movepools which pretty much consist of every single move (apart from a few).
1) Arceus. http://pokemondb.net/pokedex/arceus 2) Smeargle. http://pokemondb.net/pokedex/smeargle 3) Mew. http://pokemondb.net/pokedex/mew
Ditto. Now Ditto can have any moveset in existence, but does not learn the moves himself. So this might count too.
So of course, there is no movepool compared to these Pokemon as these Pokemon have a movepool of all moves in existence.