Among the professional Republicans, Ross Douthat joins Greg Mankiw in opposition to Steve Moore. So far, they are the only two I have seen—and Greg Mankiw is the only economist:

Ross Douthat: Why are people up in arms over Steve Moore for the Fed?: "The consensus in conservative academic think tank land is that Moore is an enormous hack, and this was true long before his Trump boosterism. Trump wants to nominate him because he's against Fed tightening, which is probably correct policy, but Moore pretty clearly is only taking that view because it's Trump's view and he likes Trump...