Doorbell & doorbell cams
Doorbell cams have become very popular, and for good reason. They add security with event triggered recording available, you can see when packages are delivered in their field of view, and if you have a smart door locking system you can see who is at the door in case you need to allow someone access while you are not able to answer the door personally.
Not all doorbell issues are related to cams though. Sometimes doorbells just need to be repaired, the button, transformer, or ringer replaced.
And not all cams are limited to doorbells. There are spotlights with motion activated cameras, standalone cameras that can be installed around and inside your home for monitoring and security.