What is the strongest type of wood glue?

Any wood glue is fine and will be stronger than the wood it's self when done correctly. Titebond is Excellent, and is also available in a waterproof version (Titebond3), as well.

Keep everything clean, clamp the joint, firmly without crushing the material, and don't expect end grain, to glue up strong, no matter the species of wood. Research how to glue up wood if you don't know, it takes more than good glue to make a good joint, in wood.

PS wipe up your glue squeeze out, with a damp rag.