I didn't see a generalised thread on this, so I thought I'd throw out a few ideas for items and materials, and would of course welcome other members to post their own suggestions as well.
Basic items:
Yarn = Axe + Twigs
Arrowhead = Stone + Axe
Charcoal - Wood + Fire
Tools:
Fishing Rod = Yarn + Twigs (allows you to catch raw fish)
Spear =Twigs + Arrowhead (basic hunting tool. Lower rate of catching fish, and also a basic weapon)
Ember = Charcoal + Fire (Behaves like fire, but can be used multiple times)
Skills:
Cooking - Gaining by combining meat/fish with fire, which results in burned meat/fish until learned
Fishing - Causes Fishing Rod to catch larger fish, which satisfy more hunger
Foraging - Increases the rate that bushes regenerate nuts & berries
Scout - Increases walking speed slightly