Very simple, absolutely effective!

The are small tasks that are not suited for complex apps with GTD, projects, notes. You just need a word or two to remember them and it is generally quick to complete them but sometimes you just cant work on them immediately. What you need is the ability to enter the tasks and a time/date very quickly. Small Task does just that in a seamless way and with 3D Touch support.

Matsoc about SmallTask - Simple To-Do List, v3.1