The phrase "be simpatico" means to have a like-minded or harmonious relationship with someone. If you are looking for synonyms to describe this type of relationship, there are several options. You could say that you and someone else "click" or "get along well." You might describe yourselves as "compatible" or "in sync." Other synonyms for "simpatico" include "on the same wavelength," "in tune," "in harmony," or "in agreement." Regardless of the terminology used, the idea is that two people have a positive connection that allows them to work together smoothly and enjoy each other's company.