Computer Keys. The last word of each theme answer is a key found on a PC Keyboard. Placement on your keyboard may vary.
17-Across. It may provide arch support: SHOE INSERT.
22-Across. First house: STARTER HOME. See above.
45-Across. Skill of elite WNBA players: BALL CONTROL. Often abbreviated as CTRL.
And the Unifier:
And two bonus computer references:
47-Down. Enter one's credentials: LOG ON.
54-Down. Screen image: ICON.
Across:
17-Across. It may provide arch support: SHOE INSERT.
22-Across. First house: STARTER HOME. See above.
45-Across. Skill of elite WNBA players: BALL CONTROL. Often abbreviated as CTRL.
59-Across. Emergency exit with a ladder: FIRE ESCAPE. Often abbreviated as ESC.
And the Unifier:
37-Across. Internet troll, slangily ... and a hint to the ends of 17-, 22-, 45- and 59-Across: KEYBOARD WARRIOR. I am not familiar with this term for internet trolls.
And two bonus computer references:
47-Down. Enter one's credentials: LOG ON.
54-Down. Screen image: ICON.
Across:
1. "__ my best": I DID. I did my best to make the commentary amusing.
5. Like many action film stunts: RISKY.
10. SpongeBob SquarePants' boss, e.g.: CRAB. A reference to a television cartoon.
14. Noblewoman: LADY.
15. Remove, as a knot: UNTIE.
16. Cut with a beam: LASE.
19. Leave out: OMIT.
20. "Good Hands" company: ALLSTATE. // And 58-Across: 20-Across' hands symbol, e.g.: LOGO.
21. Ready to swing: AT BAT. Think baseball. // And 45-Down: Pitching miscues: BALKS. Another baseball reference.
25. Big name in electric cars: TESLA.
29. Corp. bases: HQs. As in HeadQuarters.
30. Badges worn by conference attendees: ID TAGS.
32. Letter after sigma: TAU. It's Greek to me.
33. Grammy winner Erykah: BADU.
40. "Need You Tonight" band: INXS.
41. __ Angeles: LOS.
42. Give false hope to: LEAD ON.
43. Fertilization targets: OVA. Plural of Ovum.
44. Petri dish gels: AGARS.
52. Stay away from: AVOID.
53. Reclusive: HERMITIC.
61. Tae __ do: KWON.
62. Personal belief system: CREDO.
63. Lustrous gem: OPAL.
64. IDs on 1040s: SSNs. As in Social Security Numbers.
65. Salad green: CRESS.
66. Hatchling's refuge: NEST.
Down:
1. Rick's love in "Casablanca": ILSA.
2. "Charlie and the Chocolate Factory" author Roald: DAHL.
3. Winner of a TV talent show: IDOL. A reference to American Idol.
4. Tints: DYES.
5. Attack on foot: RUN AT.
6. Photo-sharing app, briefly: INSTA.
7. Take the wheel: STEER.
8. White wine apéritif: KIR. This liqueur appears with some frequence in crossword puzzles.
9. At this time: YET.
10. Dishrag, e.g.: CLOTH.
11. Stallone's one-man army: RAMBO.
12. 2007 Alicia Keys album that won three Grammys: AS I AM.
13. Actress Midler: BETTE.
18. "We're on!": IT'S A GO.
21. Horror trio?: ARs. As in the letter "R".
23. Remove from the deep freeze: THAW.
24. Fifty-fifty: EQUAL.
25. __ torch: party light: TIKI.
26. Biblical paradise: EDEN.
27. Underworld river: STYX.
28. Yellow or chocolate dogs: LABS. As in Labrador dogs.
31. Cannon barrage: SALVO.
32. Many "NFL Live" highlights: TDs. As in Touch Downs.
33. Speak highly of oneself: BRAG.
34. Verdi opera set in Egypt: AIDA.
35. Opportunity metaphor: DOOR. When one door closes, another door opens.
36. Coffee vessels: URNS.
38. Dappled horse: ROAN.
39. Emperors' domains: REALMS.
43. Neatnik's possible condition, briefly: OCD. As in Obsessive Compulsive Disorder.
46. Promises with gusto: AVOWS.
48. Pride members: LIONS.
49. Midafternoon hour: THREE. As in 3 o'clock.
50. Marsh grasses: REEDS.
51. Sandwich cookies: OREOS.
55. UPS Store supply: TAPE.
56. Bitter craft beers, briefly: IPAs. As in India Pale Ales.
57. Irish person, e.g.: CELT.
59. TV monitor: FCC. As in the Federal Communications Commission.
QOD: The main dangers in this life are the people who want to change everything ~ or nothing. Nancy Astor, Viscountess Astor (née Nancy Witcher Langhorne; May 19, 1879 ~ May 2, 1964)