1. Get a grade other than an F → PASS
2. Mattress supporter → SLAT
3. Toy that can go "around the world" → YOYO
4. You might let these "fall where they may" → CHIPS
5. A chef might wear a puffy white one → HAT
6. Chocolate treat designed to look like a mountaintop → SNOCAP
7. Actress Ryder of "Beetlejuice" → WINONA
8. Baseball's Mel → OTT
9. " ... in that range" → ORSO
10. Mary who sings "In every job that must be done there is an element of fun" → POPPINS
11. So great it's unnerving → SCARYGOOD
12. Georgetown athlete → HOYA
13. Put in a good word, perhaps? → EDIT
14. Something circled on a calendar → DATE
19. Presentations during a product unveiling → DEMOS
20. Move, to a Realtor → RELO
25. More than 10 billion of them are currently in circulation in the U.S. → ONES
26. Plaints of puppies → YIPS
28. One with many Insta followers, perhaps → CELEB
29. Fancy feather → PLUME
30. Toy cube inventor Erno → RUBIK
32. Scottish negative → NAE
33. Test an OB may perform in the second trimester → AMNIO
34. Silly → INANE
35. Football player with a team name inspired by the California gold rush → NINER
37. Where meats and cheeses are often displayed → DELICASES
41. Blunder → ERR
42. Vegetable that looks like a large scallion → LEEK
43. Girls Who ___ (nonprofit promoting women in computer science) → CODE
45. Incomplete sets on sale → ODDLOTS
46. Source of motivation, in modern lingo → INSPO
48. Verb preceder, typically → NOUN
49. Most sagacious → WISEST
50. Parent's declaration in response to defiance → ISAYSO
54. New ___, capital of India → DELHI
55. "Get outta my hair!," in a text → MYOB
56. Discipline for the flexible → YOGA
57. Rage → FURY
58. Ripped (up) → TORE
61. Phrase sometimes chanted after a dare → DOIT
62. Canadian gas brand → ESSO
63. Element with the symbol Ne → NEON
65. Last of 26 letters → ZEE
66. Initialism on a Navy carrier → USS