Firebird RDBMS offers ANSI SQL features & runs on Linux, Windows & several Unix platforms. Features excellent concurrency & performance & powerful stored procedure & trigger language.
More information and downloads at https://firebirdsql.org/, issue tracker is https://github.com/FirebirdSQL/firebird/issues
The Joseph Project is a financial software (Income, expenses, bill payment, bank reconciliation...), multi-plataform (Windows/Linux/Palm-OS) Client/Server, that can be used by companies, small busines, personal finances, churches, non-profit, etc.