I am new to Home Assistant, so sorry if this seems like a dumb question and is on the wrong section of the forum. I am confused about what sensors I can add to Home Assistant. Does everything I can add need to be on this integrations page (https://www.home-assistant.io/integrations/)?
P.S. If anyone could recommend any Bluetooth occupancy sensors, it will be very much appreciated.
No, not at all. There are also a wide variety of third party custom integrations.
Unfortunately there is no central list for them. Though a lot are being added to the HACS list of repositories, Google search for something like “home assistant [your device here]” is your best bet.
I tried iBeacons. Wasn’t great but I think I purchased the wrong type.
As well, many of the integrations are gateways to many other things. The MQTT sensor for instance provides support for any sensor that can communicate over MQTT.
For that I just use phones, but I’ve also got a Chipolo tag I use with monitor (see here too).