Raw Materials: Seeds: Seeds are used to grow wheat, and can be found by tilling grass or harvesting fully-grown wheat.
Slimeball: A bit of goo dropped by slime (small).
Snowball: Obtained when a snow block (drops 4 snowballs) or snow (drops 1 snowball) is destroyed with a shovel of any type. Snowballs cause no damage, but do provide a knockback.
Stick: Used as a crafting ingredient for many things. Sticks are good.
String: Used in crafting with no outside functions.
Sugar Cane: Sugar cane is used to create paper and sugar. It can be planted on any grass, sand or dirt block located immediately adjacent to water.
Wheat: Grown when farming by planting seeds. Wheat is used for cooking. It can also be used to breed certain animals by feeding them when in a group of two or more.
Wool: Dropped by sheep when they are killed, but best obtained from sheep by using shears. Wool can be dyed into 16 different colors and is used for decoration or crafting.