68 known values for trail with current usage counts:

1. default (27674× used)
2. fluff (9582× used)
3. yellow_dots (5858× used)
4. red (2705× used)
5. blue (1754× used)
6. paws (1471× used)
7. green (1388× used)
8. fire (1317× used)
9. rings (1306× used)
10. earth (1065× used)
11. ice (937× used)
12. arcade (933× used)
13. red_neon (838× used)
14. stardust (715× used)
15. ice_dust (570× used)
16. blue_neon (569× used)
17. flowers (553× used)
18. fire_dust (545× used)
19. sakura (519× used)
20. shadow_dust (471× used)
21. magic (394× used)
22. autumn_leaves (389× used)
23. crimson (386× used)
24. digital_3d (318× used)
25. shadow_tail (316× used)
26. fire_tail (301× used)
27. abstract_3d (251× used)
28. elements (243× used)
29. ice_tail (241× used)
30. magic_tail (226× used)
31. magic_dust (199× used)
32. wish (175× used)
33. black_and_white (76× used)
34. speedy (72× used)
35. stars (67× used)
36. tech_path (60× used)
37. pollution (50× used)
38. tracks (45× used)
39. leaves (42× used)
40. green_neon (41× used)
41. siren (37× used)
42. feathers (36× used)
43. treasure_map (31× used)
44. snowflakes (30× used)
45. zzzzz (29× used)
46. propulsion (29× used)
47. festive_tree (29× used)
48. red_dots (29× used)
49. aaaaa (28× used)
50. pumpkins (28× used)
51. twinkles (25× used)
52. dots_inc (21× used)
53. lunar_fireworks (19× used)
54. bubbles (14× used)
55. rainbow_light (10× used)
56. bomb_fuse (10× used)
57. ghost (9× used)
58. blue_plasma (9× used)
59. money_trail (8× used)
60. lucky_trail (8× used)
61. rainbow_dots (8× used)
62. confetti (7× used)
63. red_plasma (5× used)
64. gold_dust (4× used)
65. spacewar (4× used)
66. gold (2× used)
67. musical_notes (1× used)
68. meteorite (1× used)