I have found some ... weird looking blocks while playing around with the new setblock command. There might be more :
/setblock ~ ~ ~ minecraft:cocoa DATA (replace DATA by any number between 12 and 15 inclusive)
/setblock ~ ~ ~ minecraft:pumpkin_stem DATA (replace DATA by any number between 8 and 15 inclusive)
/setblock ~ ~ ~ minecraft:melon_stem DATA (replace DATA by any number between 8 and 15 inclusive)
Playing around with blocks that aren't supposed to be in the game could very well be buggy. If you want to cheat them in, be prepared to accept the consequences.