His symphony #4 "Italian" is a true orchestral warhorse, filled with tunes you're sure to find familiar and quite invigorating. Many superb versions of it are out there (Stokowski, Szell, and various others come to mind), but none I've ever heard surpasses Van Beinum/Concertgebouw in a splendid mono (but hi-fi) recording from the early '50s. I've cherished my LP copies for at least two decades, but it's hard to find in CD form unless one frequents the Japanese online stores.
Much of Mendelssohn's chamber music is beautifully rewarding. Seek it out and sample whatever you find.
Enjoy the hunt.
Dirk