Minecraft wiki entry for Development_versions, associated text: Podzol.
Mycelium.
Huge mushroom blocks.
Cocoa.
End portal frames.
Double plants.
Dark Oak and Acacia Wood
With their Stairs, Slabs, Planks, and Leaves variants.
Saplings:
Jungle saplings,
Acacia saplings,
Dark Oak spalings.
Stained clay (In all its 16 colors).
Lilypad.
12 new Flowers:
Blue Orchids
Alliums
Azure Bluets
Tulips (red, orange, white, pink)
Oxeye Daisies
Sunflowers
Lilacs
Rose Bushes
Peonies.
Red sand.
Hardened clay.
End stone.
Granite
With it's polished variant.
Diorite
With it's polished variant.
Andesite
With it's polished variant.
Emerald block
Emerald Ore.
Packed Ice.
Version exclusive: Grassless Dirt.