There is a list of spreadsheets on Wikipedia:
https://en.wikipedia.org/wiki/List_of_spreadsheet_software
Spreadsheets that don’t yet have a page on this website include the following:
Planmaker — http://softmaker.com/english/ofwpm_en.htm
Gnumeric — http://gnumeric.org/?ckattempt=3
Spread32 — http://byedesign.co.uk/
Abykus — http://abykus.com/
GS-Calc — http://www.citadel5.com/gs-calc.htm
Sphygmic — http://www.softpedia.com/get/Office-tools/Other-Office-Tools/Sphygmic-Software-Spreadsheet.shtml
EditGrid.com — https://en.wikipedia.org/wiki/EditGrid
Wingz — https://en.wikipedia.org/wiki/Wingz
Improv — https://en.wikipedia.org/wiki/Lotus_Improv
S2020 — from Computer Associates