It can help to have a visual aid when trying to get something done, but what sort of style? Most to-do apps use lists, of course. DropTask is a little different—it lets you create flow charts of nested circles to represent the different tasks you have to get done.
The app has a more standard list view of your projects, but it's the "visual view" that makes DropTask distinct. You can drag down from the task and group labels to create new ones and organize them however you like. You can place groups and tasks inside other groups to create stratified tasks. Each circle also comes up in the list view elsewhere in the app, but the chart UI could be really useful—like a map of getting stuff done. Collaborators can be assigned to different parts of the project, and their photos will hop around the diagram as they work on things.
You can only create five projects and have one collaborator with the free version—it's unlimited with pro. A pro subscription also offers extras like new themes, cover images, and email task integration. It looks like the app comes with a 30-day trial of pro. The ongoing subscription is handled through DropTask's website, and it's $6.50 per month.