This is Tweek: the best planner app I have ever used!!!
I'm one of those people who can't get anything done without a list to cross things off of. Tweek is great because it's super minimalist, free to use, and most importantly really AESTHETICALLY PLEASING!!!
The basic functions are a daily calendar, which you can add tasks to. Tasks can be different colors, and when you finish them you can cross them off your list. Unfinished items will be immediately moved to the next day, and you can set reminders for timed tasks!!
I probably went through at least six mediocre planner apps before I found this one. If you love simple, cute lists, you're going to LOVE Tweek!!!