https://potapp.co/#/doc/new/readme Notes&todo app. You write everything like it's a document, and then view/change todo items on a kanbad-like board. I would love to hear some feedback.
I like this idea. Writing a memo and adding tasks while writing, maybe assigning to some people. The only drawback is that there are already so many todo apps. However it could be a good idea if it could work together with some Todo apps like Todoist.