Is there any way to make calls ring/vibrate only for specific contacts?
see there i don't know any direct method but we can apply some trick to it.
(i am assuming that we want to make all other calls silenced and only your call can ring or better we can say make sound.)


open voice recorder and record silence. Name that recording as per your convenience.
now go to the settings and change call ringtone to the one you just now recorded and save the change's made.
now go to the dialer and select your contact and now edit your contact info.
(at this you need to be careful as every android device has this feature in different ways) From there in setting's select a special ringtone for your contact


Thus when others call it will sound silenced and when you actually call than it will ring the tone you specifically selected for you.