The 16 Personality Types are widely attributed to Swiss psychiatrist Carl Gustav Jung, who published the Psychological Types book in 1921, combined with the subsequent work of Katharine C. Briggs and Isabel Briggs Myers (aka Myers-Briggs™).
Jung’s work on personality types centered primarily around four functions (Sensing, Intuition, Thinking and Feeling) combined with two attitudes (Extraversion and Introversion).
Jung called these his 8 types:

1. Introverted Sensing
2. Extroverted Sensing
3. Introverted Intuition
4. Extroverted Intuition
5. Introverted Thinking
6. Extroverted Thinking
7. Introverted Feeling
8. Extroverted Feeling

According to Wikipedia, Myers-Briggs “extrapolated” from Jung’s theories to produce the Myers-Briggs Type Indicator (MBTI) ™ assessment, which developed four pairs of preferences/dichotomies:

1. Extraversion (E) versus Introversion (I)
2. Sensing (S) versus Intuition (N)
3. Thinking (T) versus Feeling (F)
4. Judgment (J) versus Perception (P)

From those dichotomies came these 16 personality types:

• ISTJ
• ISFJ
• INFJ
• INTJ
• ISTP
• ISFP
• INFP
• INTP
• ESTP
• ESFP
• ENFP
• ENTP
• ESTJ
• ESFJ
• ENFJ
• ENTJ