I love so many boys names (including the first and middle names of my boys). There's so many, many boys names in the "sweet spot" of not being too popular but still great names.
Names I think that fit this criteria (in various different styles): Ross, Rex, Tobias, Dominic, Owen, Peter, Jonah, Max, Seth, Joel, Andrew, Callum, Zachary, Lewis, Nathaniel, Edwin, Emmett, Eli, Isaiah, Barnaby, Xavier, Nicholas, Gregory, Aaron, Christopher, Asher, Lucien, Ellis, Orson, Magnus, Otis, Rupert, Sylvester, Robert, Nathan, Jonathan, Josiah, Elias, Anthony, Adrian, Michael, Douglas, Finnegan, Alasdair, Jared, Victor, Dashiell, Stellan, Anders, Marcus.
Agree though about checking the ONS list for inspiration though if the above don't help!