1. Before she was Eleven on Stranger Things, Millie Bobby Brown played Ruby, a young girl who called the hospital after her mom was seriously injured:
2. American Horror Story actor Sarah Paulson guest starred as a young Ellis Grey in a flashback episode:
3. Before he was listening to Hannah's tapes on 13 Reasons Why, Dylan Minnette played an adorable little boy waiting for an ear transplant:
4. Before starring in Mad Men and The Handmaid's Tale, Elisabeth Moss played Nina, a woman accompanying her sick mother to the hospital, on Grey's:
5. Thor: Ragnarok star Tessa Thompson guest starred as Richard's niece Camille, who passed out during her prom because of her ovarian cancer:
6. Long before This Is Us, Mandy Moore played Mary, a patient who helped Bailey try to save Charles during the hospital shooting:
7. Hamilton star Leslie Odom Jr. played one of the patients undergoing the domino kidney transplant in Season 5:
8. Parenthood star Mae Whitman guest starred as a character who was admitted to Seattle Grace with a spinal problem:
9. Star Trek star John Cho played Marshall, an intern who gets into a car accident after falling asleep at the wheel:
10. Scrubs alum Sarah Chalke joined Grey's for a powerful episode inspired by her son's real-life disease:
11. Friday Night Lights and Fargo star Jesse Plemons played a character who checked into Seattle Grace with a brain tumor:
12. Scream Queens alum Abigail Breslin guest starred as a young girl who was insensitive to pain in Season 3:
13. Timeless and Pitch Perfect 3 star Matt Lanter guest starred as Adam, a high school football player with a spinal cord injury:
14. American Horror Story and The 100 star Adina Porter played a neurosurgeon who was called to Seattle Grace after Derek suffered a hand tremor as a result of the plane crash:
15. Wet Hot American Summer alum Ken Marino played a patient who had been shot by his former employee in Season 2:
16. Iconic Ghostbusters star Ernie Hudson guest starred as a surgeon on a rival baseball team in Season 8:
17. Long before she started saving the world on The Flash, Danielle Panabaker played a patient on life support after her heart had to be removed:
18. Roseanne star Sara Gilbert played Kim, a patient with terminal cancer who decided to end her life with aid from a physician:
19. Before American Horror Story: Cult, Leslie Grossman played a woman with hypochondria who diagnosed herself with cancer:
20. Friday Night Lights star Zach Gilford guest starred as an Army vet who made the painful decision to amputate his leg so that he could return to war:
21. Long before Candice Patton was kicking ass on The Flash, she played a character with a knee injury on Grey's:
22. While she was running with werewolves on Teen Wolf, Holland Roden swung by Grey's and played the mother of conjoined twins in Season 8:
23. My So-Called Life and Star Trek: Discovery star Wilson Cruz guest starred as the fiancé of a patient admitted to the hospital on his wedding day:
24. Scream Queens alum Keke Palmer played Sheryll, a patient who was hoping to be a part of Cristina’s heart surgery trial:
25. Arrow star David Ramsey played a husband who accompanied his wife to the hospital after she had been shot in Season 6:
26. Before UnREAL, Constance Zimmer guest starred as Alana, a physician adviser who was brought in to help the hospital avoid bankruptcy:
27. Parenthood star Max Burkholder played Duncan, a little boy who needed heart surgery, in Season 5:
28. Teen Wolf and Pretty Little Liars alum Cody Christian played a boy whose father thought he was faking his severe stomach pain:
29. And finally, Liza Weil, Bellamy Young, Joshua Malina, Katie Lowes, Jeff Perry, and Scott Foley all guest starred in episodes of Grey's before going on to star in Scandal:
Correction: A previous version wrongly identified Abigail Breslin's character's symptoms. There's 14 seasons, y'all — we aren't perfect.