My backyard looks like a childcare centre.
We have a cubby on stilts with a sandpit underneath and a slide attached. The sand is strewn for metres either side. It's on this weird gravel driveway (we're in company housing), and Nate has as much enjoyment from carting gravel in his bid dump trucks as he does from the sandpit. We have a swing set adaptable for different ages. We have a trampoline but due to the heat here that only gets used half the year.
We have a vege patch they're allowed to play in and a bit of dirt set aside for them to dig and mix in.
We have a sand and water table that's used for all sorts of things not just sand and water.
They have a table and chairs but they also have an art table that's a bit higher and used for making/painting under the verandah
They have their bikes/scooters/gyrobikes (very cool and a great toy)/skateboard etc that they can ride under the verandah
totem tennis
bucket of large chalk