I have a dog crate for broodies, which is mostly used to sit on top of. Also a box for garden furniture pillows which I use to store all the chicken stuff in, that is also great to sit on top of especially as it gets really warm in the sun there.
I use a hark sometimes to loosen the earth which is great for digging in.
Oh, and one purchased toy I have which was worth it, is a ball to put pellets in. I sometimes fill it in the evening, especially if I expect to sleep a little longer, and it's always empty when I open up for them to free range so they clearly enjoy the ball more than the regular feeder haha. But it would get lost in their garden, so I only leave it in the small run which they can access 24/7.
Other than that, I would say their favourite activity is to take a run in the morning as I open the pen to their free ranging area, so having enough space to take a decent flappy unobstructed run is great.
And my lead hen loves to jump up on my shoulder and have a chat. I think interacting with the hens is worth more than any toys money can buy. Whether that's holding and cuddling them, clicker training tricks, just watching and talking to them or any other kind of activity fitting the relationship you wanna have with your birds. So the fact that it's right next to the house and easy to take my coffee with the hens is also a good one.