In survival mode, minecarts drop weirdly named minecart items.
Rideable minecarts will drop a minecart named 'entity.MinecartRideable.name'.
Chest minecarts will drop regular minecarts named 'Minecart with Chest' as well as a chest.
Hopper minecarts will drop regular minecarts named 'Minecart with Hopper' and a hopper.
Furnace minecarts will drop a minecart named 'entity.MinecartFurnace.name' as well as a furnace.
Tnt minecarts drop tnt and a minecart named 'entity.MinecartTNT.name'
Command block minecarts drop a minecart named 'entity.MinecartCommandBlock.name'.

It is important to note that all of the minecarts dropped had a name in italics (similar to when renamed in an anvil) and were regular rideable minecarts, apart from their names. All other items dropped were normal.