Hmmm, I really need to see both sides of the leaf and the shape of the tree to make a more accurate guess, but I suspect it is a Sassafras tree based on the shape of the leaf and the description of the pods.  I suggest you look up images of the Sassafras tree online and see if they match your mystery tree.  The egg sacs on the back of the leaf could be a beneficial insect, so I would not worry about them as the tree is otherwise healthy.  Often, unusual trees can sprout up in the landscape when birds or squirrels plant the seeds. One warning on Sassafras trees: they have roots that can be long-ranging, so keep them away from any septic systems. Keep growing, Marianne Binetti