Wood joints:

Mortise & Tenon joints:

There are Mortise & Tenon joints which are wood pieces cut specifically in shape for a number of wood pieces to combine. They're cut specially to give them more surface area for glue since the glue provides the best point of strength in the product. You can see in the picture how the wood joins to the corners, allowing more glue to be spread out providing stronger points in the product itself.

Dowel joint: 

Dowel joints join products together by using a dowel and keeping them in line. They ensure accuracy, and have a grooved surface to allow glue to flow easily along it, allowing the joint to combine from the dowel easily and very effectively.

Dove tail:

Dove tails are cut specifically to slot together and spread glue out over a further distance, and make a very clean fit when together. It allows it to resist forces applied to the joints.

Lapped:

Lap joints are good for they increase the area being glued to keep the product itself more strengthened.
They're also neater for they show less end grain.

Finger joints:

Finger joints are good for they are similar to Dove tails, yet easier to make due to the less odd angles.