What cable is needed to connect a M2 Mac Mini to a display monitor?

It depends on the monitor. The most common monitor inputs are:

• DisplayPort
• Mini DisplayPort
• HDMI
• USB-C –for connecting video, sound, and downstream hub ports using a single cable

Many monitors have two or more of these types of inputs, to give you flexibility in making a connection, and to allow you to share a single monitor between two computers.

You can get USB-C to {DisplayPort, Mini DisplayPort, HDMI} adapter cables. So between the Mini's USB-C/TB ports and its HDMI port, there's a lot of flexibility in how you connect your "up to two" monitors.

Assuming you have a monitor recent enough, HDMI will likely be your best option, keeping your usb-c slots available fir other stuff

The Mac mini can use most any external display.

see > Connect a display to Mac mini - Apple Support

For a cable connection solution, please post the brand and model # of the external display.