I agree that the biggest question is what interests you. ID can be taken many different directions and for each one there’s probably a minor that could help.
Textile design certainly could be a practical choice if you were interested in softgoods (bags, cases, shoes, various gear) or furniture design. As mentioned above, graphic is good if you may veer towards interaction design or possibly some ID that is a bit more “graphical” or communicative. If you’re just trying to up your presentation game I’d just take one graphic design basics course and choose another minor. I got minors in Sociology/Anthropology and Mechanical Engineering Technology and enjoyed both. Sociology/Anthropology is less directly applicable unless you’re going towards design research (then it’s practically required), but it does help with understanding people a bit. Mechanical Engineering Technology (a more practical, less theoretical variant of Mechanical Engineering) is useful daily for me in building strong structures, creating mechanisms, and understanding manufacturing processes.
There are lots of others as well. Ceramics, jewelry, sculpture, electrical engineering, computer science, business, and probably others could all be useful depending on your design sensibilities and intended career path.