[Eset]

I've noticed that there's MBTI/Enneagram combinations that automatically make me question people's types.

For instance:
INFJ 5w4
ISxP 7
ISTP/INTJ 8
INTJ 4
ENTP 5

It's not like these types don't exist, but rather that they are horribly memefied to the point where people who wish to see themselves as archetypes (not specifically referring to "Jungian archetypes" although you can explore this concept using that construct as well) will adopt them together, leading to a potentially large bias in MBTI/Enneagram intersection when it comes to self-typing, or people typing other people.

I wonder if other people have noticed similar trends, potentially with other types, or the ones I already mentioned.

INFJ 5 is the second most common type for INFJ after type 4.
ISTP 7 isn't that rare, not as common, but not rare.
ISFP 7 also isn't rare.
ISTP 8 is pretty common.
INTJ 8 isn't rare, for sure most are type 1 or 5, but I often find type 8 in their tritype one way or another.
INTJ 4 is pretty common in their tritype.
ENTP 5 isn't rare.

I'll show you some really rare combinations.
ISTJ; 2,7,8.
ISFJ; 3,4,7,8.
ISTP; 1,2,4.
ISFP; 1,3,8.
INTJ; 2,4,6,7,9.
INTP; 1,2,3,7,8.
INFJ; 3,7,8.
INFP; 1,3,7,8.
ESTJ; 2,4.
ESFJ; 4,5,7,8.
ESTP; 1,2,4.
ESFP; 1,5.
ENTJ; 2,4,9.
ENTP; 1,2.
ENFJ; 5,8.
ENFP; 1,3,5,8.

 

[Eset]

Source: Here : Time of recording: 25/03/18 : From: Me

This is what I have collected from counting all the users with an MBTI type and an E type from this site's database.

Source: Here : Time of recording: 20/8/14 : From: Dalton

Same thing I did but 4 years ago, seems like they were able to gather a larger pool size, not sure how.

From these 2 sources you can make what you want from it.