Whenever I need to guess how much time a workflow is going to run (based off of the number of documents it has to process), I use a "Search Repository" task to query the parent folder with {LF:Name="*", Type="DS"} & {LF:LOOKIN="(parent folder)".  Then I click on the "Test Search Query" to get a count of the number of documents.  I can then narrow the parent folder to reduce the number of documents.

I realized I had a bunch of reports I was running monthly, and re-built them all as workflows that generate emails.  The results all come from various database queries and searches, from 4 different databases, but I can access them all from Workflow.  I have the workflow cycle through each result, it determines if the iteration of the loop is even or odd and creates a line of HTML code that includes colors (that's why the even and odd are different, since there are different colors for the two) - basically I'm building the row of a HTML table for each result, and adding that to a multi-value token.  Then at the end, it creates an email that starts and ends the HTML table, putting the token with the rows into the body of the table.  The end result is that I get my query results as a pretty HTML table in an email, automatically on whatever schedule I need it.

Note - you should probably edit this and change it from the question post to a discussion post.