Those two products that #Rahul has noted are as follows:
1. TagVault-Magnetic is a device designed to magnetically hold an AirTag onto anything steel.
2. TimeCapsule is basically a battery device that replaces the button battery in the AirTag, which lasts maybe a year, with two much higher capacity AA batteries providing longer life.
Neither of these devices do anything without an Apple AirTag. An Apple AirTag is a tracking device that ONLY works for you if YOU have an iPhone or iPad or Apple Macintosh. If you don't have any of these Apple devices, an AirTag is of no use for you. In that case you'd need an Android equivalent or something similar that works with your smart device operating system.
Though I'm not familiar with the Android or other equivalents, I do have four AirTags employed. Three are in luggage, and one on the Pagoda. They report the location back to my iPhone via the Apple app "FIND MY", the same app that tracks your family and friends when they allow it, as well as all your Apple devices when set up to do so. Mine tracks all my Apple devices (computers, iPads, phones); my immediate family members, and my four AirTags.
As mentioned in other threads, the AirTags work by "finding" any Apple device connected to the internet, and reporting their location through that device back to you via the FIND MY app. To prevent "stalking" if the AirTag moves with an unknown Apple device, the AirTag will notify that device that they are being followed by an AirTag. It does not report every connection to every Apple device.
Thus, when the AirTag is in luggage, as soon as passengers on the plane and or ramp workers at the airport come close to the luggage, the AirTag location is reported back to me. If the Pagoda is parked somewhere, say at a car show, it will report back upon request any connection to a passerby with an iPhone, but will not notify the owner of that iPhone. If a stranger (or thief!) with an iPhone takes the Pagoda, after some period of time it will notify them that they are being tracked by an AirTag.
Hardly a perfect anti-theft device, but quite useful when I bought all four AirTags for USD $99--
A true standalone GPS tracker will require a much costlier investment as well as subscription fees.