Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
Quicken - Stay in control of your monthly cash flows, budgets, and expenditures. Quicken provides a navigable interface where you can organize your debit, credit, and savings, and build good habits accordingly.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Digit - SMS bot that monitors your bank account & saves you money
The Bat - The Bat! is a secure desktop email client for Windows, designed to protect your correspondence against third-parties and to save your time.
Money Manager Ex - Money Manager Ex is a free, open-source, cross-platform, easy-to-use personal finance software.