What limits on national powers can be derived from the tenth amendment?

The 10th amendment basically says that any powers that the Constitution doesn't give to the federal government or keep the states from having automatically are reserved for the States.

One example would be that since constitution doesn't give the federal government control over marriage laws, each state gets to decide its stance on things like marriage.

Another example would be that the federal government doesn't control driver's license age restrictions, each state can set its own limits.