Oakley is my youngest's middle name. Other o names are Oliver, Oscar, Othello
Omar is lovely name for a baby boy
I like Oakley
Osaiah
Owen
Oriley
If I remember right, your first baby is named Owen, yes? I like Oakley, but maybe Oswald, Oscar, Otis, Orlando, Odin, or Otto could work.
I have also been poking around the good old interweb lol and have also found some other ones..here goes.. Octavius, Odell, Oswin, Orlin, Odrhan, Omri, Onyx, Orfeo, Orlo, Oren, Ozymandias, Oxley