I recall that the class of 1946 had two who became president: Kennedy and Nixon, and I believe the first Congress also had two future presidents: Madison and Monroe. Offhand, I'm curious if there are any other multi-president congressional classes.
The 23rd Congress (elected in 1832) saw freshmen Congressmen Franklin Pierce and Millard Fillmore.
William H. Harrison and John Tyler were both elected to the House in 1816 by special elections during the 15th Congress.
Martin Van Buren and James Buchanan were both in the class of 1820, although the former joined the Senate, and the latter the House.