Sleepover - films, pizza, popcorn, sweets, all bed down in the living room. Maybe make some tents/a den with sheets.
Traditional party - pin the tail on the donkey, pass the parcel etc. sandwiches, jelly and ice-cream.
Treasure hunt - hide clues round the house and garden and prize at the end. Could theme it if child has a particular favourite.
Pamper party - nail varnish, hair glitter, maybe some mocktails,
Tea party - everyone puts their Sunday best on, bunting and tablecloth, little sandwiches with tea and scones and cakes etc.
Disco - lights, music, crisps and fizzy pop. Maybe some glow sticks if you can get hold of them.
Sports day - egg and spoon, sack race, beat the goalie etc. Medals for everyone.