I think there will only be a handful unhappy.
Brazil, Germany, Spain, Belgium, Denmark are the glaring ones.
Disappointed you’d probably have to go with
Wales - Did so well to get there, and just couldn’t get going
Serbia - Won a difficult group involving Portugal to get there, then couldn’t stop conceding
Mexico - perennial second rounders, so going. Out in group would be disappointing.
Canada - clearly knocked from the opening match and the pen miss, feel they may have felt they could have done better.