Here's a small list or related figures that I had done a while back for a Heroclix scenario:

Spitfire, Union Jack (1 & 2)
Thanos, Starfox, Nebula
Corsair, Cyclops, Havok, Vulcan, Jean Grey, Cable
Sean Cassidy, Black Tom Cassidy
North Star, Aurora
Deathstroke, Ravager, Jericho(?)
Wolverine, X-23, Viper (wife)
Pheonix/Jean Grey/Marvel Girl, Cyclops, Havok, Cable, Vulcan, Hound, Rachel Summers (Grey)
Juggernaut, Professor X
Scarlet Witch, Quicksilver, Magneto
Scarlet Witch, Nocturne, Nightcrawler, Mystique
Hulk, She-Hulk
Jessica Jones, Luke Cage/Power Man
Hank Pym (Antman, Giantman, Yellowjacket), Janet Pym (Wasp), Stature
Thor, Loki
Psylocke, Captain Britain
Banshee, Black Tom Cassidy
Reed Richards, Sue Storm, Human Torch, Franklin Richards
Ultron, Jocasta
Vision, Scarlet Witch
Kang, Immortus, Iron Lad (all same person)
Commissioner Gordon, Batgirl/Oracle
Catgirl, Cain
Wonderman, Reaper
Invincible, Omni-man
Cuckoos, White Queen/Emma Frost
Storm, Black Panther
Black Bolt, Medusa, other Inhumans
Jade, ?
Raven, Trigon
Vindicator, Heather Hudson
Aleta, One-Who-Knows
Power Pack
Wonder Woman, Hippolyta, Nu’bia
Hawk, Dove
Colossus, Magik

Here's another list I had made of couples (even short lived ones):

Wolverine (House of M) – Mystique (House of M)
Black Bolt – Medusa
Angel – Psylocke
Thunderbird – Psylocke
Banshee – Moira McTaggart
Beetle/Techno – Songbird
Mimic – Blink
Annihilus – Blink
Cannonball – Lila Cheney
Cpt. America – Sharon Carter
Chamber – Husk
Cloak – Dagger
Absorbing Man – Titania
Ult. Thor – Ult. Valkyrie
Wolverine – Silverfox
Deadpool – Copycat, Typhoid Mary
Dr. Strange – Clea
Daredevil – Echo, Elektra
Forge – Storm
Gambit – Bella Donna, Rogue
Hawkeye/Goliath/Ronin – Mockingbird, Moonstone, Wasp, Echo (Ronin)
Corsair – Hepzibah
Hulk – Betty Ross, Jarella
Havok – Polaris
Adam Warlock – Gamora
Cyclops – Jean Grey, White Queen (Emma Frost)
Colossus – Shadow Cat
Black Panther – Storm
Spider-Man – Mary-Jane, Gwen Stacey, Black Cat
Reed Richards – Sue Storm (Invisible Woman)
Vision – Scarlet Witch
Wonder Man – Scarlet Witch
Ant/Giant Man – Wasp
Wiccan – Hulkling
Ultron – Jocasta
Silver Samauri – Viper
Juggernaut – She Hulk
Flash – Iris Allen-West
Batman – Catwoman
Green Lanter (Kyle) – Jade
Question – Huntress
Joker – Harley Quinn
Superman – Lois Lane
Superman (KC) – Wonderwoman (KC)
Cable – Domino
Green Lantern (John Stewart) – Vixen, Hawk Girl
Braniac 5 – Supergirl
Robin/Nightwing – Starfire
Thor – Jane Foster
Power Man (Luke Cage) – Jessica Jones (Jewel)
Hellboy – Liz Sherman
Professor Charles Xavier – Moria McTaggert, Lilandra
Silver Surfer – Shalla-Bal, Mantis
Thing – Alicia Masters
Iron Man – Iron Widow/Black Widow
Big Barda – Mister Miracle
James & Heather Hudson
Madame Hydra/Viper – Wolverine (black mailed)
Quicksilver - Crystal
Nova (Frankie Ray) – Human Torch
Longshot – Spiral
Spitfire – Union Jack 3
Namor – Emma Frost, Susan Storm
Ult. Beast – Ult. Storm
Aleta, One-Who-Knows (forget his real name)
Superboy, Wondergirl
Raven, Beastboy/Changeling

Soon we will have Mary Jane

And maybe her cousin Gwen Stacy

When did they become cousins?

Sorry about the Robertson/Prowler one. For some reason I kept thinking one version was Robbie's son. The others are all correct.

To my knowledge yes they still are married.

Also, we got another one today. Kraven and the Chameleon are half-brothers.

And another one from the figures previewed at SDCC. Molten Man is the stepbrother to Liz Allen. Liz and Harry Osborn were married, though now divorced. So Molten Man had a family tie to Norman.

Besides maybe passing each other at the wedding, I don't see any real relation to each other.

It kinda was a focal point of one issue, when Harry kidnapped Molten Man, Liz, and Normie Osborn (Liz and Harry's son) and tried to justify him being Green Goblin. It eventually ended with Molten Man beat down and Harry claming Liz wasn't a "true Osborn" because she wasn't related by blood. Also, it's been shown that Molten Man is close to his sister and to nephew, attending baseball games and even being blackmailed by the Chameleon to go bad again to keep Normie from getting harmed. There is a relation in my opinion, though now seperated by divorce. But your list your call

Added
Comedian & Silk Spectre (Sally Jupiter)
-Silk Spectre (Laurie Juspeczyk)

The LE Toxin figure is the offspring of the Carnage symbiote like Carnage is to Venom.

Thank you, and added.

Aren't Spitfire and Blade now a couple according to MI:13 continuity?

Not entirely accurate, actually.

While the *original* Carnage symbiote was the offspring of Venom, that symbiote was lost when Venom "permanently" re-absorbed it from Cletus, leaving him powerless.

He then, through a staggeringly stupid coincidence stumbled upon an EXACT replica of the old Carnage symbiote in the Negative Zone (DON'T ASK!) which he rebonded with to become Carnage once more. It's this new, "negative zone" symbiote that Toxin is the offspring of, and thus he has absolutely no "blood" connection to Venom at all.

High Evolutionary is Adam Warlock's 'father' isn't he? Sorry if this has already been mentioned.

No. More of a mentor, Adam was created by multiple fathers in the Enclave.