My girls are a bit older but here is what we have
- Swing and mokey bar set
- Trampoline
- Bikes, trikes and scooters
- buckets and shovels, a play tea set, spoons. At mums they have old baking trays and love using them
- sand and water table (mud table at the moment)
- balls, more balls, hoola hoop, plastic tennis racquets
- dirt and the dogs water bowl (not meant for play but both very popular)
- butterfly nets (they rarely catch anything but like trying) plastic magnifying glass for bug hunting
- plastic basketball hoop
- totem tennis (not up yet)
- paddling pool for when it gets warmer
- a picninc rug they can take outside
- plastic table and chairs which is great for outdoor playdough and other messy craft activities
- bubble blowing machine and bubbles
- chalk board and chalk
- sometimes old paint brushes and buckets of water to 'paint' the concrete

that sounds like heaps but they spend loads of time outside when the weather is fine!