Its supposed to happen 18 dec. MY PREDICTION:
My predictions (18 sets):
Death Prophet RARE
Another Marci ULTRA RARE
Alchemist (minotaur)
Nature Prophet
Anti-mage (cowboy)
Another Snapfire (snail) RARE
Slark
Morph
Another Primal Beast
Void Spirit (bird) VERY RARE
Pudge
Another Ursa (mechanic)
Oracle (yoga)
Naix (green)
Underlord (magnus father)
Bane (big)
Lion (vitorian)
Zeus (goku hair)
Source: https://www.reddit.com/r/DotA2/comments/zmxmfw/collectors_cache_2_sets_prediction_18_dec/