Multiple port numbers to use multiple appium instances

Please suggest port numbers list to start multiple instances of appium. Currently i am able to use only 2 sessions for appium - 4723, 4475

Why not use other common alternate ports? 8080, 8081, 8082, 8888, 4444, etc. should be ok if you don’t run web/HTTP servers or other Selenium servers/nodes on those port numbers. Any free port # should do I assume.