The quick simple answer would be.ArchangelApoWerewolfLongshotAbomIcemanRed MagBlack Widow DOShe HulkBut really to give your question any truly helpful answer, then it would be good to know where you are at progression while.Which content do you focus on and you are doing next?Then people can give you advice on who to rank up to tackle those content.
none of these are great defender options But you do have some that would be decent defenders and good for roster development iBomIcemanLongshot those are among the best defenders you have that will also help you do contentnone of these are great defender options But you do have some that would be decent defenders and good for roster development iBomIcemanLongshot those are among the best defenders you have that will also help you do content