I have been using Workflowy and Excel to track Scrum Sprints for several years now and it is ultra simple and flexible.
Here are the links to WFx Chrome extension and the PowerPack set of mechanics which will give you access to the Workflowy Story Point Counter.
https://chrome.google.com/webstore/detail/wfx/jbehgpdjkcconnaagjhddddfdajbpfhi
https://rawbytz.gumroad.com/l/WFxPowerPack
