Well i have an idea that may get you the results yo are looking for. IF you look towards the Gruul clans from Ravnica then they have the creatures you are looking for such as
rubblehulk. Theros has the enchantments and also in Theros the hydra creatures that are able to give themselves +1/+1 counters repeatedly! Try checking them out, I know the monstrosity will
catch your eye, especially after you add some red to it.