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.
ONLYOFFICE - ONLYOFFICE is a complete office and productivity suite.
Apache OpenOffice - Apache OpenOffice is an open source, office document productivity suite.
G Suite - Google's encompassing suite of cloud-based business apps.
Polaris Office - Polaris Office is the most compatible all-in-one office suite that lets you create and edit documents for free.
Google Drive - Access and sync your files anywhere