RS PRO, DEGSON, Amphenol, Wainelectric, and specialists like Lemco Précision, offering various types for industrial, automotive, and aerospace uses, often with gold or silver plating, suitable for different wire gauges (AWG) in heavy-duty or standard D-sub connectors. 

When choosing, consider the specific connector type (e.g., D-Sub, HDC), wire gauge, plating (gold for better conductivity/corrosion resistance, silver for cost-effectiveness), and the required performance (e.g., sealed, high vibration).