I've just held onto random ones I've run across, e.g. itags have been reasonably popular for a while: https://devices.esphome.io/devices/ble_itag and during BLE / IoT bursts of hype random things are sometimes handed out for free at and around events (not often programmable, but that's usually fine - they broadcast a unique ID when powered / when pressed, that's all you really need).

I also have one of these because I get a lot of use out of newsblur and figured I'd support the maker (I don't actually recommend it because it's pricy and not very well supported... but it's functional and flexible): https://www.kickstarter.com/projects/samuelclay/turn-touch-b...