I would like to know what these devices are. Is there any easy way to tell by the MAC addresses listed? In particular the device with the address
MAC addresses can sometimes be used to identify the maker and potentially model of the device even without the device in hand. This is called the OUI (organizationally unique identifier). Please see https://en.wikipedia.org/wiki/Organizationally_unique_identifier .
There are several lookup tools on the web , such as https://dnschecker.org/mac-lookup.php or https://www.wireshark.org/tools/oui-lookup.html . Dell has a range of MAC addresses that it uses, and Apple has another. MAC addresses are generally unique to a device, but some manufacturers re-use MAC addresses within a particular model or part number. Some devices allow you to change the MAC address advertised in software, for instance Ethernet adapters or wifi adapters. This is useful for connecting to other devices which are supposed to be locked to specific other devices (cable modems). This can be confusing.
The unique MAC address helps you a little in identifying which device is which. However, to be absolutely certain, you'll need to pair it and use it.
Some devices have their MAC addresses printed out on their shell, on a sticker, or under their battery. Some don't, or it has rubbed off with use.
If the mystery device is in range but outside your reach (possibly at your neighbor's), then there's nothing to do. Just ignore it. Some phones or laptops let you turn down the power on your Bluetooth gain and transmit, but it's more of a hassle than it's worth.
This is generally not possible. Using the MAC address, you can look up the maker of the Bluetooth radio. That’s it. Sometimes, this can give a strong hint at the type.
However, if a device is close enough for mutual data exchange, you will eventually get their name and device type using the so-called Inquiry process. It can take over 10 seconds for all devices to respond, if they are still in range. Discoverable devices respond with their name and the list of supported Bluetooth profiles.
Obviously, Bluetooth discovery is not a passive process. It can be detected.
I came here looking for the same answer to the OP's question. I don't think this question should have been closed and have indeed found the answer to the OP's query.
You can use the first 6 characters of a MAC address to find out the vendor or manufacturer name. Using the website https://macaddress.io/ you can enter the first 6 characters of a MAC address to find out the manufacturer or company name who has registered that block of MAC addresses.
The one in question ( 88:6B:0F:5A:5D:18 ) is showing as registered to Bluegiga Tech OY. A quick Google search reveals what devices this company produces:
Products Bluegiga develops and manufactures short range wireless connectivity systems, including Bluetooth modules and access servers, Wi-Fi modules, Bluetooth Smart modules as well as a licenceable embedded Bluetooth stack, iWRAP. The products are mainly aimed at adding wireless connectivity to industrial customers' products, rather than being consumer-ready end products by themselves. Common industry sectors that use Bluegiga's products include, Healthcare, automotive, audio, industrial and consumer applications.
So, more likely an industrial Bluetooth module.
Of course, the answer above does touch on this but wanted to make it clear at least you have a starting point when you only have the MAC address to work with.