What games did schoolgirls play in the 1950s?

Of course, the answers will depend largely, on which country, state or county are you speaking of.

In Australia, schoolgirls in the eastern states played netball [mainly called just "girls' basketball", at the time] and they played rounders.

In Western Australia, they also played field hockey.

These constituted the 'official' games/sports they played.

In addition to these more formal activities, girls loved playing skippy, where they used a long rope and each girl took turns to 'jump into' it. They also played hop-scotch, knuckles, ball catchy games of various kinds, kiss chasey with the boys, hula hoops and 'Queenie-queenie, who's got the ball?'

'I spy' remains a favourite game of young ones to this day.