Exclaimer - Exclaimer is the industry's leading provider of email signature solutions, empowering businesses to unlock the potential of email as a key digital advertising channel.
LibreOffice - Free office suite, open source, and compatible with .doc, .docx, .xls, .xlsx, .ppt, .pptx files. Updated regularly – download for free. Originally based on OpenOffice.org.
Sigstr - Email signature marketing
Microsoft 365 - Boost your productivity with reliable access anywhere with services like email, calendar, file sharing, meetings, instant messaging, and Office Online
NEWOLDSTAMP - Email signature generator
ONLYOFFICE - ONLYOFFICE is a complete office and productivity suite.