OpenStreetMap
The free, community-built map of the whole world.
Google Maps remembers every place you search, every route you take, and every stop you make, then ties it to your account to sharpen its advertising profile of you. A private maps app keeps your movements on your own device instead of in a company's location timeline. The trade-off is fewer live extras, since real-time traffic and rich business listings are thinner but for most trips an offline, OpenStreetMap-based app is more than enough.
Start by deciding how you travel: if you often lose signal or head abroad, prioritize an app that works fully offline by letting you download maps ahead of time. Check that it draws on OpenStreetMap, the open community map that keeps you out of any single company's tracking system and that it does not require an account just to navigate. Then weigh navigation quality, including turn-by-turn voice guidance, search, and hiking or cycling layers, against simplicity, since the most powerful apps can also be the most cluttered. Finally, favor open-source projects that are actively maintained so the code can be audited and the map data stays fresh.
Here are some things to look for.
The free, community-built map of the whole world.
Offline OpenStreetMap navigation with no ads or tracking.
Powerful offline OpenStreetMap maps with deep customization.
Community-run fork of Organic Maps, offline and not-for-profit.
Ad-free open-source public transit planner