TickTick

TickTick is an agenda app for organizing all the things you need to do on a daily basis. Its interface is elegant and easy to use, so you can tackle your day-to-day tasks – including appointments, meetings, deadlines, etc. – with ease.

Adding tasks on TickTick is simple and easy. You can also assign any of your tasks to a specific date and set reminders so you don't forget about them. When you finish a task, just tick it off the list.

In the settings, you can customize TickTick's interface. The blue theme is the default one, but you can choose from several other colors too. Other options even let you lock the app with a code.

TickTick is a great app for managing all your pending tasks. Its strengths include a simple and elegant interface, plus a good number of customization options.