TL;DR Email - Send short emails & read emails as fast as you read Facebook
Empathize - Manage your credit cards & loan in 1 place
Spark Mail - Spark helps you take your inbox under control. Instantly see what’s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues
Inbox Creature - A super cute virtual pet, delivered right to your inbox.
mlist - Email newsletters, outside of the inbox
Relief - The free app that gets rid of your credit card debt