Harth Gate Valkyrie

(If {w/u} was paid with {w}, this is white and blue.)
Vigilance, Flying
{t}: Target creature has flying this turn.
{4}{w}: Choose a color and/or artifact. Put a
+1/+1 counter on each creature of the
chosen color, excluding nonartifacts if you
chose artifact. Activate this ability only if
Harth Gate Valkyrie is white.