He everyone,
I am a History major looking to get into museum work (planning on attending Grad school for Museology). What would be a good major to pair with History for a double major?
It depends on your inclination. I watched successful careers that combined anthropology (archaeology) and history for museum work. There were also those who specialized in public education and history in museums, so an education degree might be useful.
Whatever you do, make sure you are great (not merely good) at writing. You'll need to reach the public with concise sentences. Taking whatever English department classes is necessary is a good idea.
I sat on hiring committees at museums throughout my career. I would be most impressed with a history degree combined with coursework in ethnography and archaeology with writing skills. This would probably be best demonstrated on paper with a second major in anthro - if that suits you. Take what interests you. That is the clearest path to doing your best. Having done your best is the clearest path to employment.
If at a school with a library program check if they have a BS program, some like Illinois do. Sociology and education are also very handy 2nd majors in both fields.
I have a MA in History an MSLIS in Library Science and am working on a PhD in Public History. My undergraduate majors were History and Education.