Ive had many interesting potential attractions over the years, but found especially ISTP and INTJ to have the greatest potential - both in the moment and long term.
Somehow the opposite NiSe in both of them, combined with the introverted thinking to balance out my extraverted feeling tendencies work brilliantly together.
We each have our own turf, work neatly besides one another, handing back and forth situations to each other in full confidence of each others skills, with no qualms about our own limits. If that is not possible, we encourage and advise the other as they attempt their version of our skillset and forgive them their mistakes as they figure it out.
Meanwhile, INTPs, ISFPs and oddly ENFJs of the right caliber make a great second choice. That means an ISFP who isnt conflict avoided and secure in his Fi, an ENFJ who does NOT have control issues and lets his inferior Ti run rampant and an INTP who has an exceedingly well developed Ne to keep a lid on the black and white tendencies of his Ti scalpel.
It is my experience that these conditions arent always present in these types, making them and the corresponding attraction rare to come accross.
INFJs and I do seem to share a passing fascination with each other but we invariably end up in each others turf and disagree strongly about how to do the work needed there.
Their typical need to dampen Fi 'coz its too unruly, childlike and naive' according to their judgement and enlist their teenage Ti to be ' the saving hero' and introduce the supposed much needed rationality coz they feel too closely involved for comfort makes me feel like a stupid child being send to her room 'to let the grown ups talk'. I rarely take kindly to that kind of treatment and its about the biggest turn off possible to be condescended to like that
That said - I am in awe at what they can do when they are in their element. It is also endearing to see them bristle and feel lost when presented with a mirror for self reflection. Feeling vulnerable in front of others is definitely something that only the brave ones dont run from. Its inspring to see them pluck up the courage to take those first unsteady steps to use their brilliant analytical insights on themselves for a change
Ive met the odd Infj where this was barely an issue, bit it was still present, so on the whole, they re great partners in crime at a distance, ime.
We end up taking turns on the stage as it were - observing and appreciating each others work from afar (i find they tend to bite their nails til im done as a stress response, and i find myself frowning at times at the things they gloss over until i see the end result

) and learning what we can from a distance. That way, the respect and friendship works brilliantly, but it is unsuited to my needs regarding a more intimate pairbond - and theirs, from what ive seen.