The 16 personality types based on cognitive functions: INTJ, INTP, ENTJ, ENTP (NT Rationals), INFJ, INFP, ENFJ, ENFP (NF Idealists), ISTJ, ISFJ, ESTJ, ESFJ (SJ Guardians), and ISTP, ISFP, ESTP, ESFP (SP Artisans). Each type has unique cognitive function stack (Ni, Ne, Si, Se, Ti, Te, Fi, Fe) that determines how they process information and make decisions.