52 known values for icon with current usage counts:

1. default (29492× used)
2. angel_wings (8221× used)
3. crown (6248× used)
4. joystick (6179× used)
5. moon (3985× used)
6. sakura (2151× used)
7. cat (1864× used)
8. dog (1638× used)
9. spider (1209× used)
10. pumpkin (718× used)
11. vampire (621× used)
12. headphones (547× used)
13. target (512× used)
14. sunglasses (510× used)
15. moustache (365× used)
16. coffee (306× used)
17. skill_issue (271× used)
18. panda (213× used)
19. snowflake (159× used)
20. santa (109× used)
21. reindeer (72× used)
22. pirate_flag (72× used)
23. king (68× used)
24. wizard (68× used)
25. octopus (62× used)
26. yeti (51× used)
27. bad_bunny (50× used)
28. rocket (48× used)
29. wanted (46× used)
30. lunar_dragon (45× used)
31. koala (37× used)
32. ghost (31× used)
33. planet (29× used)
34. pyramid_eye (29× used)
35. mountains (28× used)
36. bread (24× used)
37. pirate (24× used)
38. bingo (19× used)
39. cactus (18× used)
40. robot (17× used)
41. fossil (16× used)
42. shark_attack (16× used)
43. cute_bunny (15× used)
44. watermelon (14× used)
45. eliminated (11× used)
46. clover (9× used)
47. ankh (6× used)
48. pine_tree (6× used)
49. shooting_star (2× used)
50. jailbreak (2× used)
51. build_off (2× used)
52. eleven (1× used)