|I used 541100 Legal services which is under Professional, Scientific, & Technical Services. My reasoning was that I am an ex-officio notary public by virtue of being a justice of the peace. Both these offices, in my state, are in the judicial branch of government. I account for the small amount of income I get as a justice of the peace together with my notary income as one business. (Justice of the peace income consists of being paid as an election worker.)|
Some of the other suggestions are loan or real estate related. They wouldn't seem suitable for a notary obtained most of his/her income from general notary work rather than real estate signings.