Apps Run The Cloud is an internet site where almost all (if not all) Cloud Applications are referenced. They provide frequent surveys such as Cloud Application Vendors revenues and ranking.
This is the link to the home page: https://www.appsrunthecloud.com/
The top 500 Cloud Applications Vendors ranking
This is the link to the survey: https://www.appsrunthecloud.com/vendors/cloud_top_500_applications_vendors
The Top 10 Cloud Application Vendors
Salesforce, Microsoft and SAP are the top 3 vendors.
The TOP HCM Application Vendors
Workday is the 1st HCM Cloud Vendor with highest market share within HCM market and second best YoY Growth.