These are Some Ideas I came up with for low Tier Items and Blocks.
Bricks
Can be made out of clay.
Brick Block
Can be made out of Bricks.
Reeds
Can be found on the edges of water growing in it, is used to make a thatch roofing.
Rocks
An item which is generated which are like Flowers, can be collected and used in creation of primitive tools. (Can come in the different stone types)
Rock Shards
hand made, crafted using rocks, can be used to make Primitive Weapon type.
Tree Branches
An item which has a chance to drop when leaves are broken, can be used in the creation of primitive tools.
Primitive tools
Can be made out of Rocks, are lower quality then wooden tools, however they are easier to make and can be made in only a few seconds, only Axe, Shovel and Hammer can be made in the primitive tier.
Primitive Weapon (spear)
Can be made out of rock shards and tree branches, it is a melee weapon and looks like a spear.
Wattle and Daub Block(s)
Can be made out of mud or dirt and tree branches, quick to make and can come in many different variations for customisation. (Depends on Type of dirt used or mud)
Thatch Roofing Block(s)
Can be Made out of reeds or leaves and tree branches, quick to make and can come in many different variations for customisation. (Depends on type of leaves or reed used)
Cobbled Rock
Can be made out of Rocks, looks similar too Metamorphic stone, however it looks more random and chunky. and is of a darker shade. (Depends the type of Rock used)
Branch Fence
A fence piece which looks like it was made out of sticks, easy and quick to make, only needs tree branches.
Primitive Stone Fence
Similar to cobbled rock however it is thinner and is easier to make and quicker, made out of rocks.
These items and blocks will allow us to make Iron age style Round Houses and other such structures.
Feel free to suggest your ideas and any changes you would make, any feed back is welcome.
Also feel free to post pictures of real life structures you would want to make with these materials.
I would make these style of buildings with these materials:
Edit: Added Bricks.