What to hoard:
1. Stone Age
a. Wood
b. Stones
c. Flint Stones
d. Berries
e. Mushrooms
f. Resin
g. Feathers
h. Beech seeds

2. Bronze Age
a. All kinds of wood
b. Stones
c. All kinds of leather (Troll!)
d. All kinds of meat
e. Copper
f. Tin
g. Greydwarf eyes
h. Resin
i. Blueberries
j. Carrot seeds
k. Thistle
l. Feathers
m. Oak and birch seeds

3. Iron Age
a. All kinds of wood (Ancient!)
b. Stones!
c. All kinds of leather
d. Roots from Abominations
e. All kinds of meat (don't cook the boar meat!)
f. Iron from crypts
g. Turnip seeds
h. Blood bags
i. Intestines

I haven't progressed any further yet. :D

Did I miss something?

Edit: Oh yeah, Iron Age you need gunk. Farm it. You want it.