Is db_executor a standard role in SQL Server 2012 R2? In trying to figure out the exact permissions I need to give a user to execute all stored procedures I ran across many pages saying to create a role of "db_executer" and give that role the GRANT EXECUTE permission, then assign users to that role. When I when to my sever to make that role I found out it already exists. Since I inherited this server I am not sure if it was made by the last admin, a program, or is a built in. Searching Google I am not finding any relevant hits newer then 2010 and those all talk about how to make the role. Can anyone tell me if this is a default role in 2012 or if someone/thing else made it?
db_executor is not a default role (MS has a list of default roles), it would have been created by somebody.

There's also no SQL Server 2012 R2. Potentially you are getting confused with Windows Server 2012 R2.