Go (golang) library for reading and writing XLSX files
An R package to create styled tables in multiple output formats
csv2odf can convert csv data to formatted spreadsheets and documents.
C++ library for creating XLSX files for MS Excel 2007 and above.
C library for reading/writing values from/to Excel .xlsx files.
VBA add-ins which convert Microsoft Office contents to various formats
Ability to work with large csv files and cut them down to run in Excel
Extract data in CSV format from PDFs
Serializes and Deserializes objects into spreadsheets
Query Abstraction Layer
Open source Extract Transform Load engine written in Java