The phrase "miscellaneous category" refers to a group or collection of various or different things that do not fit into specific categories or classes. It is like a catch-all group for items that don't have a specific classification. Full definition
Xiaomi slipped to fourth place with 35 % fall in sales and Samsung Galaxy phones failed to hit the top five at all, being grouped into the «Others» miscellaneous category by IDC. (9to5google.com)
Try to avoid having a Miscellaneous category as much as possible! (noguiltmom.com)
Usually, a miscellaneous category like «other» has a fairly insignificant monetary figure allocated to it — if youhave a lot of «it, you create a special line item (like «Centrifuges»). (sciencemag.org)