If you want a GPS tracker that can be disguised among your valuables and that has long battery life, there are several models from Invoxia that could work for you. The Mini Tracker is designed to blend in with your belongings and has a battery life of up to 3 months. It offers live location updates, geofencing and proximity alerts, so you can keep tabs on your assets and get notifications when they enter or leave a specific area.
Another possibility is the Petcube system, which includes GPS trackers that are built into pet cameras. The devices offer real-time location updates, escape alerts and virtual fences, so they could be used to track pets or other valuable items. The system requires a GPS tracking subscription, which starts at $5 per month.