What are some apps that you have on your phone for programming and development? (Android)

I want to make a phone designed for programming. I want to use something like the pine phone and either load or make a custom OS for this purpose. I've found my self sitting some where doing nothing and having an idea that I would like to test but either don't have a laptop or don't have the space to use my laptop (Lenovo x240). I would love to hear your suggestions for base phones and custom ROMS or OS to use. I am on a bit of a budget however I would be willing to spend a bit along as it's worth the price.