I've been working on HODLings, a private crypto tracker, which doesn't track you!

https://www.geosystemsdev.com/products/hodlings/

In essence, it runs on your mobile device and stores all your data locally. It only connects to the freely available CoinGecko API (for latest prices) and GitHub (for reference and historical data). A background job updates GitHub ref data hourly. There's no login, no cloud, no ads, etc.