Figure a list of the most convent mons might be fun.

So far even though my fav are Alakazam, Gardevoir, and ghost types honestly the most useful I've found so far are Beedrill and Butterfree.

Those 2 bug types breed fast, evolve fast, and can haul.
With just 2 weedle and passive training you can raise an army of Beedrill / Butterfree almost instantly for all your hauling and defending needs.