This is a weird question and suggests some real discomfort between the volunteers and the executive director.  Most people would think it would be perfectly appropriate for the executive director to thank the crafters for participating in the event and some of them may be expecting a formal note of thanks.  (They won’t be able to deduct much for the work given to the raffle table because an artist can only deduct the cost of the materials, and not the fair market value of their personally-produced work, given to a charity.)

It is particularly weird to withhold the crafters’ identities when it doesn’t appear that they were hiding secretly behind curtains at the fair or that their identities were withheld from the prospective purchasers of their work.  A few questions to people who attended the fair could probably identify a good portion of the crafters who helped out.

I am not aware of any legal reason why the volunteers would have to identify the vendors who participated in the fair if that is not one of the ground rules in advance.  But I can think of a number of reasons the charity would want to know to say thank you and to assure that there is no improper favoritism among those selected.  If the volunteers are afraid that their personal contacts will be “stolen” from them, they ought to be able to work this out in a conversation with the exec or the board officers.  But the entire effort is to support the charity, and it is a shame to see that the volunteers’ unhappiness with the executive director could undercut that purpose.