My lame attempt:
1. Justice and Songbird. They have a LOT in common. Both have been to prison. Both are Jewish. Both are former wrestlers. Both had abusive fathers. Both fly around with pink energy.
2. Cannonball and Firestar...I think this was Firestar's first kiss...I always kind of wanted them to date for real. Justice's saving sex until marriage thing while honorable but didn't strike me as realistic...I never got the vibe Angel wanted that.
3. Speedball and Boom Boom....to me they have very similar personalities.
4. Moonstone and Loki...to me Karla is a narcissist so she would naturally want someone exactly like herself. But she doesn't want someone crazy like Baron Zemo. She wants a manipulator not a fascist.
5. Glorian and Runner...same look.
6. Karolina Dean and Lightspeed...both like girls, both have rainbow powers.
7. Madelyne Pryor and Kaine. Both have the whole evil clone thing going for them. She's telepathic and he has psychic visions.
8. Deathbird and Thanos. Both have blood feuds with siblings. Both killed their mother. Both have offspring they don't like to claim. Both like to conquer. Thanos likes death and so does Deathbird...because you know she calls herself Deathbird.
9. Thundra and Sharon Ventura. I mean you can't tell me there isn't rampant lesbianism going on on Femizonia. Plus we know Thundra likes Ben Grimm but I don't think she's ever gotten with him. So Sharon is a Thing she can bring home to Femizonia but you know still fits her rock creature fetish.
10. Fixer and Typhoid Mary. I had to think and long and hard to find someone for my favorite character Fixer. The way I see it Fixer doesn't have much in the way of prospects so he needs to lower expectations because he will never find a smart woman with a good head on her shoulders. So he would zero in on really damaged women. But he's shallow and misogynistic so he wouldn't date a total dog like say a rocky Sharon Ventura. But he's also really scummy so he wouldn't get classier crazier chicks like say Aurora. To me Typhoid is just the right combination of damaged, trashy, and desperate to make Norbert happy.
Cyclops and Wanda - before Disassembled and House of M, of course. I always thought they would be great together.
Ben Reilly and Gwen Stacy's Clone
Thor and Thundra.
Daredevil and Black Cat
Beast and Dazzler
Tony Stark and Janet Van Dyne
Rick Jones and Jane Foster
Mar-Vell and Carol Danvers
Adam Warlock and Her/Kismet
Pym and Moondragon
Colossus and She-Hulk