I think the TNT sprite could be the "Nuke" symbol, but its still TNT when its placed.
A chest could be the Mystery Box.
The cake could be the radios found throughout the maps (if you dont know what im talking 'bout, look up COD zombies hidden radios).
The pig could be the space monkeys from Ascension.
Flint and Steel could be a flamethrower.
Some of the paintings could have what is written on the walls in blood on some of the maps (ex - Beware of the 6).
THESE ARE JUST IDEAS, BUT UHH, GET WORKING! i want this TEX PACK