GnuCash is personal and small-business financial-accounting software, freely licensed under the GNU GPL and available for GNU/Linux, BSD, Solaris, Mac OS X and Microsoft Windows.

Odoo, formerly known as OpenERP, is an open-source business application suite developed in Python under the AGPL license. It follows the Open Core software business model and serves a global user base of 2 million.

ERPNext is a free and open-source integrated Enterprise Resource Planning (ERP) software developed by Frappé Technologies Pvt. Ltd. and is built on MariaDB database system using a Python based server-side framework.

Paisa is a Personal finance manager. It builds on top of the Ledger double entry accounting tool.

Dolibarr ERP & CRM is a modern and easy to use open-source web software package to manage your business (customers, invoices, orders, products, stocks, agenda, e-mailings, shipments...).

Oinkoin Money Manager makes managing personal finances easy and secure. It is light and easy to use. You need just few taps to keep track of your expenses. Simplicity and Security are our two main drivers: Oinkoin is an offline and ad-free app.

GreenStash is a simple FOSS android app to help you plan and manage your savings goals easily and establish the habit of saving money.

Skrooge allows you to manage your personal finances, powered by KDE 4.x. Thanks to its many features, it is one of the most powerful way to enter, follow, and analyze your expenses.

Manager is free accounting software for Windows, Mac and Linux.

It features an intuitive and innovative user interface with modules such as cashbook, invoicing, receivables, payables, taxes and comprehensive financial reports.

The desktop edition is free while the cloud edition.

Intuit QuickBooks is an accounting software with financial management tools like payroll management, live bookkeeping, and flexible accounting plans for all business sizes. It provides record-keeping, reporting, inventory management, and integrates with over 750 apps.

Bigcapital is a smart and open-source accounting and inventory software, Bigcapital keeps all business finances in right place and automates accounting processes to give the business powerful and intelligent financial statements and reports to help in making decisions.

Ledger is a powerful, double-entry accounting system that is accessed from the UNIX command-line. This may put off some users, since there is no flashy UI, but for those who want unparalleled reporting access to their data there are few alternatives.