There is no way to get treecko unless its from ME Mystry event but you be able to get if you get pokesav you download it pokesav.org with a manual on how to use it
you cant get it without migrating.
Near Hearthome city.
Im afraid you cant.Deoxys an only be obtained by migrating or using a cheat device(gameshark,action replay ect.)
1111009876654FC
You can't find Rayquaza it in pokemon diamond, pearl, and platinum. You just migrate it in Pokemon Emerald, ruby and saphirer
u can't
U HAVE TO MIGRATE OR ACTION REPLAY
In Diamond & Pearl? Impossible without migrating, trading, or Action Replaying.
I don't think you can get it without action replay, GameShark etc.
You can't without trading, migrating or, cheats
Unfortunately, you cannot get Cindaquil in Diamond or Pearl without migrating from a previous game.
You need an action replay. Or you beat emerald and migrate the chickorita