Alternativas ao NumSync para Firefox com licença comercial

• Firefox
  Todas as plataformas Windows Mac Linux Chrome OS Android iPhone Windows Phone Blackberry Blackberry 10 iPad Android Tablet Kindle Fire Windows S Web Self-Hosted Software as a Service (SaaS) Firefox PHP JavaScript Windows Mobile Microsoft Office Outlook Raspberry Pi Chrome Cloudron Flowinity Motti.NET (Programming Language)
• Licença comercial
  Qualquer licença Licença gratuita Licença Open Source Licença comercial