Sticks for beating, clubs, shivs, and with some skill a spear and bow.
You'll need dried willow or cattail stems for the arrow shafts.
Animal sinew or scavenged man made fiber for the string.
Add another stick to a spear and you got yourself a nice atlatl.
Sticks can also be used to make leveraged and gravity deadfalls.
Sand or even forest ground cover makes good throw-in-the-eyes weapons. Mud, for that matter as well.
Pebbles can be thrown at max velocity at close range as a shotgun effect.
If you have the materials to make a sling, small stones will poke a nasty hole in opponents.
Hand sized rocks hurt when thrown to target.
A hand sized stone hafted to a decent handle makes for a good bludgeoning object.
But again, like the bow & arrow, this is a skill and time issue.
A good ten/twenty pounder dropped from above will stove in a skull.
Vines can be utilized as snares, trip wires or as semi-binding.
Sapling trees and small branches make good face snapping weapons.
If you got the time and resources pull down something larger and lash a sharp stick to it, attach trip line and stay away.
Feces coated punji stick pits will ruin your day.
Just setting the whole GD forest on fire sometimes works, too!
Antler stems also make good stabbing weapons.