None.  At this time the only requirement to be a mentor coach is that you are ICF credentialed* at the level someone is applying or higher.  No additional training or certifications are required.   *For ACC credentialed coaches, you must have been through at least one credential renewal cycle before you are eligible. 

At this time the only requirement to be a mentor coach is that you are ICF credentialed* at the level someone is applying or higher.     *For ACC credentialed coaches, you must have been through at least one credential renewal cycle before you are eligible.