Water table, playhouse, little tikes seesaw x
I've also got a 3.5 year old but we've got - toddler trampoline - slide - rocker - bikes & scooters - sand + water - goal and balls - toy BBQ - child's table and chairs I painted with chalk paint so can draw on - bowling, badminton, golf If I had a bigger garden we'd have a mud kitchen, Wendy house & climbing frame My kids help with the gardening so they have mini gardening tools and toy lawnmower, and access to the flowers and the gardens decorated with ornaments etc
Just got a swing and sand table - I think that should be enough.
My girl has been helping out in the greenhouse despite having swing slide bike etc. so now she has a tub of plant pots and her own child size gardening tools
Water play. Either to sit in like a paddling pool or a container that you can put on a table, add water and containers to so they can fill and empty. Can use anything clean and safe from the recycling or buy stuff specifically. My girl loves putting lids back on things so don’t throw them away it just adds to it. Ride on toys - like a baby balance bike, crazy tykes car Football to kick about or throw Ball pit balls - be warned you will be picking them up all the time! Also can go in the paddling pool when not warm enough for water. Pram to push about