68 known values for trail with current usage counts:

1. default (28191× used)
2. fluff (10044× used)
3. yellow_dots (6093× used)
4. red (2848× used)
5. blue (1917× used)
6. paws (1557× used)
7. green (1501× used)
8. fire (1298× used)
9. rings (1293× used)
10. earth (1075× used)
11. ice (937× used)
12. arcade (923× used)
13. red_neon (839× used)
14. stardust (721× used)
15. flowers (632× used)
16. ice_dust (609× used)
17. blue_neon (574× used)
18. fire_dust (547× used)
19. sakura (529× used)
20. shadow_dust (511× used)
21. magic (405× used)
22. crimson (393× used)
23. autumn_leaves (381× used)
24. shadow_tail (367× used)
25. digital_3d (351× used)
26. fire_tail (323× used)
27. abstract_3d (316× used)
28. elements (293× used)
29. ice_tail (284× used)
30. magic_tail (258× used)
31. magic_dust (205× used)
32. wish (191× used)
33. black_and_white (122× used)
34. stars (73× used)
35. speedy (72× used)
36. tech_path (58× used)
37. pollution (51× used)
38. leaves (43× used)
39. tracks (43× used)
40. green_neon (42× used)
41. red_dots (42× used)
42. feathers (41× used)
43. treasure_map (36× used)
44. siren (36× used)
45. snowflakes (35× used)
46. propulsion (34× used)
47. zzzzz (30× used)
48. aaaaa (29× used)
49. pumpkins (29× used)
50. festive_tree (29× used)
51. twinkles (22× used)
52. dots_inc (21× used)
53. lunar_fireworks (20× used)
54. bubbles (16× used)
55. lucky_trail (11× used)
56. rainbow_light (11× used)
57. bomb_fuse (11× used)
58. blue_plasma (10× used)
59. rainbow_dots (9× used)
60. ghost (9× used)
61. money_trail (8× used)
62. confetti (7× used)
63. spacewar (7× used)
64. red_plasma (6× used)
65. meteorite (3× used)
66. gold_dust (3× used)
67. gold (2× used)
68. musical_notes (2× used)