Antonyms of uncommon:
common, general, popular, ordinary, standard, grassroots, average, democratic, frequent, demotic, familiar, normal, regular, customary, natural, usual, everyday, typical, unexceptional, unextraordinary, expected, predictable, plain.
Examples of usage:
  1. " I have always flattered myself that mine was an uncommon hand.
    "A Vanished Hand", Sarah Doudney.
  2. I had no time to look around me, for, old as he was, my opponent displayed uncommon activity, and I could not but admire his courage.
    "The Chevalier d'Auriac", S. (Sidney) Levett-Yeats.
  3. " Why, miss, they are uncommon civil, and I don't think after all it will be so bad.
    "Can You Forgive Her?", Anthony Trollope.