Especially for those of us with no coding background, who can’t just build/edit an app.
For example, I like using Gadgetbridge to replace my fitness tracker app: https://gadgetbridge.org/
It’s not nearly as full-featured as a regular fitness app, but it literally can’t connect to the internet so there’s no way anyone can get my health info.
TranslateYou is great! I use it for quick translations. For longer translations and conversations, there’s the less feature-rich, but incredibly powerful on-device translator, RTranslator. It is truly and incredibly impressive.
Also, there is a whole suite of “You” apps. I’ve used the recorder and the calculator and liked them a lot.