Venus opposite Pluto has always been a powerful one for me. Venus in Taurus in tight (1 degree) opposition to my Pluto falls in my 7th house and is catnip to me.
Moon in any aspect to Mars is pretty intense too.
Moon in aspect to Moon - personally this is no.1 for me in terms of emotional closeness.
Hard aspects between Saturn and inner planets. Saturn is like glue, it latches onto the other planet. Sometimes the results are good, and sometimes they are bad.
Jupiter conjunctions, especially woman's Jupiter to man's Sun or Mars.
Venus and Pluto in my case. Usually the trine. I've had it twice affect me pretty deeply.
I have a Pluto/Venus/Moon synastry aspect with a good male friend of mine. His Pluto trines my Venus and Moon. We also have Sun (me) conjunct Venus (him), Mars conjunct Mars, Mars (him) sextile Venus and Moon (me), Pluto (him) sextile Mars(me), a Uranus/Venus double whammy and a Neptune/Venus double whammy. His Venus conjunct my Neptune and my Venus sextiles his. His Venus conjuncts my Uranus and mine squares his. My Mars also conjunct his North Node. I'm very attracted to him but I'm certain he's not interested in me. I'm happy to be his friend in any case.
I also was apart of another Pluto/Venus trine with another male friend of mine except I was Pluto and he was Venus. That attraction didn't last more than a year.
Also fairly certain that his Venus (friend I'm very attracted to) also conjuncts my Saturn.
....are you really, really certain he's not interested in you? Yeah, I'm a sucker for romance stories and that synastry is a story for sure!
I know he cares about me because we're friends and tries to help out with my job search and gives me suggestions for improvement. There's an occasional sexual joke from him but that's it.
We did some sexual things last year but it waned so I really don't think he's interested in me anymore. The kicker was that he admitted he was attracted to my intelligence and thought I was attractive in general when we were out drinking one night.
I met him in one of my computer networking courses a couple of years ago as we have the same college degree. That's how that came about.
There's some other weird things I've noted about our personal lives but I don't think it's relevant. Lol.