Chipolo. Small company but it works. Doesn’t really help you find stolen stuff but you can be notified and the things can beep loudly if they are distanced from you.
It helps me find my keys and not forget anything when I leave the house. I guess they already paid for themselves by reducing the time I spend backtracking.
They also have an airtag compatible version.
Work fine for finding locally if in Bluetooth range. Not good for finding lost things outside of that. I lost some keys in July last year. Still not found since then.
Apples biggest benefit is the sheer number of phones that can help locate lost items. I was hoping Androids Find my Device network to be the same but currently it’s really lacking.