OwnTracks is an open-source device tracker app for iOS and Android that lets you publish location data from your mobile phone. On the mobile app you can locate other connected devices on a map and get help navigating to the devices/friends/family members. With OwnTracks integrated in Home Assistant, you can create automation rules based on presence detection (for example, turn on the lights when someone gets home) or just keep an eye on where your youngsters (their phones) are from within the Home Assistant GUI.
What I really like about OwnTracks is that the creators encourages you to own and handle your private location data. Owntracks has a public broker but supports sending the location data with MQTT to your own private broker instead. To achieve this in my current home automation setup, I need to bridge an external broker with my within-LAN mosquitto broker that I use for my home automation.