I found online some free Workflow Activities for SharePoint, it is worth it to take a look at them and see if they are significant for you: http://wf.netfx3.com/files/14/default.aspx.

These include:

  •  ForEach Activity
  • Workflow WebPage Activity
  • Create Word Document Activity
  • Send Email Activity
  • Create Excel Spreadsheet Activity
  • SQL Server Database Activity

Enjoy!