Does anyone know what the new effects are? I also heard there are 2 new effects for taunts.
Here are the Unusual effects for hats and taunts in Scream Fortress 2014.
Hats, from left to right: Amaranthine, Bonzo the All-Gnawing, Haunted Phantasm Jr, Ghastly Ghosts Jr, Stare From Beyond, The Ooze.
Taunts: Ghastly Ghosts, Haunted Phantasm.
(There's a chance that the taunt effects and their Jr hat variants may have been mixed up on the wiki, by the looks of it.)