Portfolio ideas for c# and xamarin forms beginner?

Question

Mobile development

Hello! Please share your ideas for a portfolio for a very junior in c# and xamarin forms.
I want to attach a simple App code to my resume (via GitHub). The degree of complexity of a task such as a simple (!) Calculator or tic-tac-toe (so that I can handle it myself), but I don’t want the calculator itself - it’s already sick of everyone. Here I sit thinking to write. Maybe some other simple game?
Since I will also try out for other c# projects, I still need a small "general" c# task, without marinas. Here I don’t know at all to come up with, tk. I have not worked in this area yet and there are no cool projects. Just a solution to a couple of problems from a problem book of some kind to write? :/
Thanks

Answer 1

List of simple projects:
https://github.com/it-shark-pro/mobile-school/blob...
Harder:
https://github.com/it-shark-pro/mobile-school/blob...

Answer 2

Previously, all clients wrote for VKontakte.