One of my children's favorite activities at that age, and for several years afterwards was "dress up." For my granddaughter at about that age, I went to Good-Will and bought some formals, petticoats, sparkly jewelry, and did a little quick altering and combining and came up with things like a "wedding dress," "royal" clothing, etc. You could decorate some sort of sturdy box for it. Be sure there is enough clothing so a friend can join in the fun.
Over the years, we added parts of Halloween costumes, capes, purses, etc, and both boys and girls in my neighborhood used our dres up box for creative play and later to make up plays which they invited the parents to watch.
Of course many little girls also like baby dolls that they can feed bottles to, push in a small stroller, etc. with clothes that are easy for small fingers to take on and off. Plastic dishes are good for tea parties. My children and grandchildren like to paint and draw, so an easel with big crayons and markers and sheets of newsprint for drawing is usually fun.
I would always emphasize toys that invite interaction and creative play. Our house was always a center for neighborhood activity because we had our garage outfitted with tack board and a tray on one wall, with lots of art materials and the aforementioned dress up things. By the way, if there are older children in the family, the smaller children love to play school, and we had a couple of old classroom desks and a blackboard with chalk as well. (I know blackboards have been replaced with whiteboards, so that would work too.)
So often, I see these expensive plastic toys, and after a few tries they are dismantled and discarded. By the way, not just boys, but girls as well, like building toys like legos, tinker toys, Lincoln logs, although to many of them, a doll house with an open side and furniture to arrange might be a great "building" toy.
S. Toji