Babu Frik is the first and only "droid-smith" that I've ever heard of. How many droid-smiths are in the Star Wars Universe?
If you're specifically looking for the term 'Droid-smith' (or 'Droidsmith') found elsewhere in canon, then the sole mention seems to be found in the Rise of Skywalker: Visual Dictionary which refers to an 'unknown droidsmith' responsible for the construction of Ochi's droid D-O.
Cobbled together by an unknown droidsmith felled by Ochi's blade, D-O is an impressionable little roller. Ochi was an assassin by trade, but he had many pastimes to while away the long stretches of time and isolation between assignments. Some of his hobbies were sinister, but Ochi also collected droid technology, and even designed and built some of his own. Ochi claimed D-O after slaying the droid's master.
Purely for the record, the term isn't found in any of the thousand or so non-canon novels either.
If you just mean 'people who can repair/rebuild droids then those are two-a-penny (Anakin, for example, and whoever broke l3-37's Imperial programming).