I started with Treecko on my first run. Kinda lackluster, but suppporting with Screech has saved me a couple times. I rebred one with Dragonbreath, Energy Ball (Treecko lvl 37 iirc), Leaf Storm and HP Fire. Potential physical coverage is much better, but its physical attack isn't great. During, my first one had Leaf Blade, Pursuit, Fury Cutter and Screech at your time in the game iirc. Ain't great, but that's what I had. Pick up Pachirisu/Emolga, they're great at what they do (crippling, taking one mon out). You can also get Wormadam-Trash/ Forretress(bug/steel), Stunky/Skuntank, Ekans/Arbok and Koffing at your point in game iirc, if you're in that much triuble with poison-types. Phanpy is also nice, and I think you could get Bunnelby there, too. Learn it EQ before evolving, tho.