I recommend Magikarp! Ah no he's gone...then Ralts! Nope gone too....hmm Magmar? Gone......ok, now seriously: for the first 2 Gyms use a Kricketune Fury Cutter will kill everything and don't forget Vespiqueen (with Destiny Bond) you will need it believe me, you can try Trubbish (with Toxic Spikes) it's useful against the early Gym Leaders also Espurr is pretty good till midgame (more or less), the really good Pokemon appear later (how it really should be in all Pokemon games imo).
P.S.
If you really have problems progressing i recommend Torchic as a starter, Blaziken puts the game on "easy" mode (well sorta)