Termux is amazing (not possible to get equivalent on iOS without jailbreak). The number of packages in the repository, as well as the speed of version updates (sometimes in line with Arch Linux - a rolling release) are really amazing.

Bought all the paid add-ons to support the developer. It's one of the most valuable assets I miss on iOS (doesn't matter that much now as I've got Linux x86_64 and ARM with me on the go).