We’ve had a couple threads on this, and it keeps coming down to the best Hydra team is to not play Hydra.
Here’s the one thread: Fun Teams [List] - #5 by Esoxnepa
Many of the Hydra Teams come down to the trait not going enough damage to be worth using it as part of the theme.
At this point, I’d probably look at something like:
Gorgotha
Hydra
Dark Priestess
Soothsayer? (Something empowered to help get the team rolling.)