With the growing list of products that Apple offers, the number of devices connected to your Apple ID can be quite large. Having all the devices connected to your Apple ID will help you keep track of them, but when it's time to share with Apple TV or Apple Watch, they can still be connected to your Apple ID. In some cases, this may affect the overall security of your account.
For your convenience, you can manage your Apple device list directly from your iPhone. I suggest that everyone do this and every now and then to check which devices are connected to your account, so you see why in a second.
Why You Should Check Your Apple ID Device List
If you no longer have one of the listed devices, whether stolen, lost, sold or given away, there is no sense that they are attached to your Apple ID. You can even find devices you don't recognize at all. In these cases, it is best to remove them.
From a security point of view, if you no longer use the device and have two-factor authentication set for your Apple ID, it is even more important to remove devices that they can use to receive 2FA verification codes when they log in to Apple or iCloud services from a new device.
Products shown in your Apple ID device list
Devices that you can view and delete in your Apple ID account Includes almost all major Apple products: iPhone, iPad, iPod touch, Mac, Apple Watch and Apple TV. AirPods are not included because they do not connect to your Apple ID, even if they will be displayed in Find My iPhone so you can track them if it's lost.
In the case of devices other than Apple, Windows 10 computers that you logged into iCloud can also display, such as a Surface Laptop 2 or Surface Go. Instead of seeing a picture of the device, machines with Windows 10 and higher will have an icon with four gray diamonds in a larger diamond shape.
Delete items from your Apple Device List
Deleting devices from the list can be done from iCloud.com, but this post will only focus on doing so from an iPhone, as it will be the easiest way for most Apple users to remove devices from their account. This is most useful when you sell, give away, or just lose a device.
Don't confuse this with the process of interrupting devices from your iTunes account, which is very similar, but a completely different thing. ITunes approved devices are for iTunes only, and you can allow iTunes use on non-proprietary devices. How to remove them in iTunes does not remove them from your Apple ID account.
Step 1: Open Your Apple ID Settings  Open the settings, then tap your name, which includes all your important Apple information, including Apple ID, iCloud, iTunes, and the App Store. The units that are connected to your account will be listed in order at the bottom of the menu. The first device listed (example: "This iPhone") will be the device you use and the rest will be your other Apple devices.
To delete devices that you no longer use, tap the name. Within the menu for Device Info go to the bottom and tap the "Delete from account" option. You will get a prompt to confirm that you want to delete it, so press "Delete" on it.
Once you delete a device, it will never appear again in the Apple Devices list unless it connects to the Internet with your Apple ID logged in. It can be annoying if you try to delete it from the list altogether, so you must be sure that you are signed in to your Apple ID on the device first.
It is also worth noting that within this Device Info menu you also get access to other important information, eg. if Search My iPhone (or iPad, iPod or Mac) is on or off.
Other data here may include Send latest location, model name, software version, serial number, IMEI, phone number and Apple Pay card, whose later can be turned off by device. This is an easy way to keep track of important information about the device that you may need one day.
Important Things to Consider When Removing Devices
If you give the device to a family member, log out of iCloud, iTunes, iMessage, FaceTime and Game Center are probably good enough. When you sell an Apple device like an iPhone or iPad, it's good to wipe the device that will remove your Apple ID information and disable Find My iPhone and Activation Lock.
When there is an Apple device that was lost or stolen, before removing it from the Apple device list, you want to use Search My iPhone to mark it as lost so no one else can use it. Wipe it on the remote control. In this way, Activation Lock prevents anyone trying to log into their own account on the device, a security measure designed to deter thieves and other suppliers of stolen goods. Then you can remove the device as described above or directly in Search for my iPhone after remote control.
If you deleted a lost, stolen, or unknown device, you may want to consider changing your Apple ID password as a precaution.