Oooh, I like the chart. Some of the markings I don't entirely agree with, but if there is data to support these then I would absolutely love to see where it came from. Could potentially be very insightful.
As far as what I see:
ENTP: 7, 8, and 3. For 7, I feel like that's honestly reserved for ENTP's who have very very weak Si, or overall aren't that developed. The ones that do fit that are often (but not always) all over the place and just barely manage to function. 8's are fairly common, but they don't always "appear" as J 8's often do. 3's are a lot more common than reported I suspect. Many ENTP's I would surmise don't want to be a 3. Three's are interesting stand alone because being seen as image conscious by an image conscious person is usually seen as bad. Overall I believe 3's are underreported, but I digress.
INTP: 5. Don't really need to say much else do I? The two have the strongest link and similarity than any other matching combination between MBTI and enneagram. 4's can appear as well, though many INTP's would likely not want to think of themselves as such. 4 is very often seen as a strictly F type, but it definitely can show up in a T manner. 9 can also happen, but I hesitate to consider it "common".
ENTJ: 8. Again, don't need to say much else. It's not nearly to the same extent as the link is with INTP-5, but 8 is almost prototypical for ENTJ's. 3 is also fairly common, but I think it's underreported.
INTJ: 5, 6, 8, 1. INTJ's are sort of unique from the NT's in that their spread of enneagram is fairly broad, with no one type standing out that much, even from the four I listed. I'd honestly argue that the only two you likely won't see are 2, and 7. Even looking around on here you'll see many different enneagram-MBTI matchups for INTJ's. Out of them I think 1 is the most underreported, in particular if the INTJ in question tends to identify with Ne somewhat. 1's are often seen as prototypical Si, but it can definitely show up with Ni. I mean, hell, I am a 1.
