https://www.xelplus.com/
Excel resource that provides online courses and tutorials.
https://excelexercises.com/
Excel Exercises helps regular people learn Excel as quickly as possible.
https://www.vertex42.com/
Excellent source for Excel templates covering all topics and industries.
Excel-Easy.com
#1 Excel tutorial on the net
https://metic.net
Never stop designing.
Pixel2life.com
Large collection of tutorials covering dozens of programs.