MBTI agrees INFJ is ENTP's ideal match. However, the best intertype relation is duality and in that sense, socionics pairs ENTP with ISFP. Why is INFJ not a duality relation? - Quora
Tools
Socionics – Intertype Relationships: A Brief Description | Backwards Time Machine
Type and subtype analyser | School of Associative Socionics
Intertype Relations | Wiki | Myers Briggs [MBTI] Amino
Relations between Psychological ("personality") Types