Final Fantasy vs. Dragon Quest II
Final Fantasy

Final Fantasy II vs. Dragon Quest III
Dragon Quest III

Final Fantasy III vs. Dragon Quest IV
Final Fantasy III

Final Fantasy V vs. Dragon Quest V
Final Fantasy V

Final Fantasy VI vs. Dragon Quest VI (one year off, FF predates)
Final Fantasy VI

Final Fantasy IX vs. Dragon Quest VII
Final Fantasy IX

Final Fantasy XII vs. Dragon Quest VIII (two years off, DQ predates)
Final Fantasy XII

Final Fantasy XIII vs. Dragon Quest IX
Dragon Quest IX