Here's my second stab at a four color deck. I've only played it twice so far; first time I got mana flooded, second time I won with a 15/15 Invisible Stalker.
At first glance the strategy is simple. Invisible Stalker for hard to remove pings that get bigger the longer the game plays out. Vastwood Hydra, Hydra Broodmaster, and Heroes' Bane for some impressive offense and defense. Duskmantle Guildmage pretty much just hangs around for Mindcrank and cause it never hurts to have a 2 drop 2/2 that can deal non-combat damage and mill (if you got the mana). Avacyn, Angel of Hope cause she's an 8 drop 8/8 with flying and vigilance and makes everything I own indestructible, and with my ramp I can feasibly play her as early as 5th turn. Archetype of Endurance, an 8 drop 6/5 that makes all my creatures hexproof and prevents my opponents from having it. I'm actually looking to replace it with a Privlieged Position once I aquire it. Kruphix, God of Horizons really only for the ramp for late game hydras, but having no limit to my hand size isn't too bad, either.
Search for Tomorrow, Market Festival, and Dimir Aqueduct for ramp. I don't like that Market Festival is so expensive but it's very useful for this deck by adding 2-6 extra mana to make up for the low number of lands of each color and a possible 30 mana for Hydra Broodmaster. This is why I threw in Search for Tomorrow; I enjoy the suspend mechanic, which allows me to play it as early as 3rd turn and allows me to cast a 4-5 drop (if I've managed to play a Dimir Aqueduct on second turn) spell that turn. Homeward Path just in case an opponent decides they want a hydra of their own.
Sterling Grove a 2 drop that gives all my other enchatments shroud. Banishing Light for removing anything I don't want on the field. Witchbane Orb to help slow the game. Sphere of Safety to slow it even more, should I need that (and even if I don't need it, oh well). Hands of Binding while not being as good as detain, has the cipher mechanic which works really well with Invisible Stalker.
Mindcrank because milling is almost always helpful, even if for only one a turn.
Dictate of Heliod turns Invisible Stalker into a serious problem and makes the hydras just a little more frightening.
Lure in case invisible stalker isn't cutting it alone.
Primeval Bounty a 6 drop everything else ramp.
Lure + Vastwood Hydra opens my opponent to attacks from other hydras and can be used to intentionally kill Vastwood Hydra to add its counters to Invisible Stalker. Also works in a pinch with other hydras to open up your opponent to larger unblockable attacks.
Mindcrank + Duskmantle Guildmage for a possible 4th turn mill and/or damage win.
Hands of Binding + Invisible Stalker to continually keep one or more of an opponent's(s') creatures tapped.
Sterling Grove + Privileged Position + Avacyn, Angel of Hope to make everything I own hexproof and indestructible, except my enchments which are shroud, hexproof, and indestructible, except Privileged Position and Sterling Grove which would be shroud and indestrubile and hexproof and indestructible respectively.... but I don't see anyone allowing me to pull this off.
I'm also looking to get a Vexing Shusher.
