Onboard or via a phone/controller? Parrot had very good SDKs but they stopped making consumer drones. You could get one used but beware that the batteries are

Onboard or via a phone/controller? Parrot had very good SDKs but they stopped making consumer drones. You could get one used but beware that the batteries are mostly aging out. DJI have a Mobile SDK, although it has a quite confusing support matrix and is artificially hamstrung on consumer drones. I think the latest mobile SDK for Android still supports the Mini 3 Pro, so that might be a good starting point (but not the newer 4 Pro). They also have a Payload SDK for their enterprise drones. Autel also have a mobile SDK although I would describe it as simply a mess. You can always build your own drone with Ardupilot or PX4 but you’ll have to deep dive into DIY, reimplement or forego a ton of basic flight functions that commercial drones already handle, like visual odometry, and you don’t get a nice camera built in. It’s a viable option for a hobby use but you won’t get anything close to even the most basic commercial drone functionality.