11 'Grey's Anatomy' Family Members That Really Should've Shown Up On The Series By Now

John Fleenor/ABC

One of the last never-before-seen members of Dr. Grey's sprawling family will finally make an appearance sometime this season. But there are still plenty of Grey's Anatomy family members left to introduce, even after Derek's fourth and final sister stops by Grey Sloan Memorial for her grand debut.

Earlier this month, it was announced that the long-running medical procedural was finally about to introduce fans to the final member of Dr. Shepherd's immediate family, Derek's sister Kathleen; and earlier this week, it was revealed that the series had cast Person Of Interest alum and current The Gifted star Amy Acker as the long-absent fifth Shepherd sibling. Previously, viewers have met Derek's mother Carolyn (played by Cagney & Lacey's Tyne Daly); his sister Nancy (played by Mad Men's Embeth Davidtz), an OB/GYN; his sister Liz (played by Scream's Neve Campbell), a doctor of unknown speciality; and of course his sister Amelia, a neurosurgeon.(Their father was murdered in a robbery when they were all very young.) Of course, Kathleen is also a doctor, having previously been revealed to be a psychiatrist.

But while Kathleen's introduction closes the chapter on Derek's immediate family, plenty of Grey Sloan docs still have unseen family members out there who could add plenty of juicy drama to the show.

1. Eric Thompson

ABC

In the interest of closing chapters on characters' sprawling families… while Derek gets his final family member to stop by the hospital, why not the final member of Meredith's complicated family as well? The last time we saw her half-sister Molly (Lexie's younger sister) was back in Season 3, when she was checked in for a complicated birth. But we never met her husband, Eric. Perhaps in the wake of Thatcher's death is the perfect time to bring Molly back after 12 years offscreen and introduce viewers (and Meredith) to her husband and daughter, Laura.

2. Amber Karev

ABC

Fans have now met Alex's late father Jimmy, his brother Aaron, and most recently his mother Helen. Isn't it about time to bring in the last Karev family member: his sister, Amber? She certainly has a tragic story; after a hard childhood being raised by a schizophrenic mother, she was later almost murdered by her own brother Aaron after his own psychotic break. All this happened offscreen, though, so it would be nice to meet the youngest Karev in the flesh.

3. Nicky Evans

ABC

Speaking of Alex's father — who passed away from endocarditis after years of heroin use — he has another son, as well: Nicky Evans, who Jimmy fathered with an unknown woman after abandoning Alex and his family. Jimmy admitted he also abandoned Nicky when he was only five years old; that kid is likely old enough now to come to the hospital and stir up drama for Alex.

4. Richard's Siblings

Eric McCandless/ABC

15 years into the show, and still not too much is known about Richard's childhood. He once revealed that his mother passed away from pancreatic cancer when he was 10, and that he had both a brother and a sister. While his father is almost certainly no longer living, it would be nice to meet Richard's siblings some day and learn more about the man behind the medicine.

5. Catherine's Sisters

Eric McCandless/ABC

Likewise, Richard's second wife has two sisters whom viewers have never met. It's kind of weird that neither of them have showed up for her wedding to Richard, her recent surgery, or any major life event. Here's hoping the writers rectify that soon; perhaps the Fox sisters can arrive to help Catherine adjust to living with cancer. Besides, wouldn't you just love to see who they would cast as Debbie Allen's sisters?

6. James Peterson

ABC

OK, so this one's only half true. Technically, Amelia's ex-fiancé has never been introduced on Grey's Anatomy… but he was a recurring character on the sixth and final season of Private Practice. Given that not every single Grey's fan watched the spinoff, though, perhaps it's time for the character — who Amelia dumped when she decided to move to Seattle and work at Grey Sloan — to make his first appearance on the flagship series, and stir up drama between his ex and Owen.

7. Henry's Sister

ABC

In the course of Teddy's short-lived marriage to handsome, doomed Henry, she never met any of his family. That's because his parents had both passed away a few years earlier and he wasn't particularly close with his sister, who lived in Prague, because his health condition was "exhausting" to talk about. But maybe it's finally time to meet that estranged sister, arriving in Seattle and bringing up memories of Henry just as Teddy is settling into the idea of raising a child with Owen and romancing Tom Koracick.

8. Tom's Ex-Wife

Eric McCandless/ABC

Speaking of Tom, he has his own tragic backstory that could rear its ugly head at any time. The outwardly cocky surgeon revealed that, years ago, his 10-year-old son was killed when he was hit in the head by a baseball, leading to the dissolution of his marriage. If things start getting serious with Teddy, you can probably count on Tom's ex showing up to complicate matters.

9. Ms. Schmidt

Eric McCandless/ABC

Jo may not have a "family" in the traditional sense of the word — abandoned by her mother at a fire station when she was an infant and then shuffled among foster homes before running away and living out the rest of her teens in a car — but she has one parental figure it would be nice to meet. When she was in high school, Jo had a favorite teacher, Ms. Schmidt, who would let her into the school early to shower and do laundry before classes. She was important enough to Jo that Ms. Schmidt was the only person who showed up when she graduated top of her class from Harvard Medical School. With the newlyweds recently reconnecting with Alex's mom, Helen, maybe it's time for Jo to reconnect with her surrogate mom as well.

10. Link's Family

Eric McCandless/ABC

Given that Atticus Lincoln was only just introduced this season, it's not surprising that fans haven't met any of his family members yet; but that also means that his backstory is basically a blank slate that the writers can be endlessly inventive with. They can introduce an ex-wife, domineering parents, a competitive brother, even a secret child… any ingredient to spice up the brewing Link-Meredith-Andrew love triangle.

11. Andrew's Father

Eric McCandless/ABC

And speaking of Andrew, the relative that fans are probably most curious about meeting — given his recent mention — is Dr. DeLuca's father. While trapped in an elevator, Andrew told his crush Meredith (in Italian) that his father is mentally ill and once operated on seven patients in a manic state and ended up killing four of them. Due to his money and influence in Italy, he was able to avoid repercussions, but Andrew has obviously had complicated feelings about his dad ever since. That confessional monologue was obviously preamble to meeting the corrupt, unbalanced Italian surgeon in the flesh, right?

Tune in for the rest of the season to meet the fourth and final Shepherd sister… and then place your bets on which long lost Grey's relative will enter the halls of Grey Sloan Memorial Hospital next.