+1/+1 Hydras Ramp (Modern)

A simple hydras deck.

Our Hydras are:
Hungering Hydra is great early to mid game. It's difficult to block and gets bigger if blocked and not killed. Synergizes well with Mutant's Prey and our combat tricks.
Protean Hydra is a worse Hungering Hydra, but still good.
Voracious Hydra is flexible and can serve as removal.
Primordial Hydra is great mid to late game. It gets really big really fast, especially if used with Solidarity of Heroes or Bioshift.
Kalonian Hydra also becomes really big really fast and takes every other hydra with it.

Hardened Scales provide lots of values since we're constantly creating, doubling and moving +1/+1 counters. It is especially useful when casting small hydras.

Elvish Mystic and Incubation Druid serve as ramp. The latter can be very effective if it gains a +1/+1 counter early on, preferably with Llanowar Reborn or Oran-Rief, the Vastwood.

Llanowar Reborn and Oran-Rief, the Vastwood helps with Incubation Druid and small hydras. If we have Hardened Scales and are casting a hydra with variable cost, it's better to use the second ability of Oran-Rief, the Vastwood than using it for mana, since this way Hardened Scales triggers twice.

Mutant's Prey is removal and activates the abilities of Hungering Hydra and Protean Hydra.

Bioshift can act as removal, combat trick or to save the +1/+1 in response to removal.

Solidarity of Heroes is either a combat trick or a way to protect against some removal.