1. 1st StreetPass tag with a Special Mii.
2. 10th StreetPass tag with a Special Mii.
3. Met five male Mii characters in a row in one trip to the plaza gate.
4. Met five female Mii characters in a row in one trip to the plaza gate.
5. Met the same Mii 10 times.
6. Collected 100 StreetPass tags in one day.
7. Met Mii characters via StreetPass five days in a row.
8. Met Mii characters via StreetPass 10 days in a row.
9. First StreetPass tag in a while. (>10 days)
   
10. First StreetPass tag in AGES. (>one month)
    
11. Met a Mii on his or her birthday.
12. Got a “fantastic” rating.
13. Got 10 “fantastic” ratings.
14. Got 50 “fantastic” ratings.
15. Got 100 “fantastic” ratings.
16. Met Mii characters from a total of two different regions.
17. Met Mii characters from a total of three different regions.
18. Met Mii characters from a total of five different regions.
19. Met Mii characters from a total of 10 different regions.
20. Met Mii characters from a total of 20 different regions.
21. Met Mii characters from a total of 30 different regions.
22. Met Mii characters from a total of 50 different regions.
23. Met Mii characters from every region in your country.
24. Met Mii characters from a total of two different countries.
25. Met Mii characters from a total of three different countries.
26. Met Mii characters from a total of five different countries.
27. Met Mii characters from a total of ten different countries.
28. Met three in a row, all in one go, who used the same software last.
29. Received a personal greeting.
30. 1st StreetPass tag.
31. 10th StreetPass tag.
32. 50th StreetPass tag.
33. 100th StreetPass tag.
34. 500th StreetPass tag.
35. 777th StreetPass tag.
36. 1,000th StreetPass tag.
37. 2,000th StreetPass tag.
38. 3,000th StreetPass tag.
39. 4,000th StreetPass tag.
40. 5,000th StreetPass tag.
41. 6,000th StreetPass tag.
42. 7,000th StreetPass tag.
43. 8,000th StreetPass tag.
44. 9,000th StreetPass tag.
45. 9,999th StreetPass tag.
46. Plaza population reached 10.
47. Plaza population reached 50.
48. Plaza population reached 100.
49. Plaza population reached 500.
50. Plaza population reached 1,000.
51. Plaza population reached 2,000.
52. Plaza population reached 3,000.
53. Got three identical Puzzle Swap pieces in a row with Play Coins.
54. Completed a Puzzle Swap panel.
55. Completed five Puzzle Swap panels.
56. Completed seven Puzzle Swap panels.
57. Completed 10 Puzzle Swap panels.
58. Made it through a room in Find Mii.
59. Missed with a sword attack three times in Find Mii.
60. Dealt over 50 damage in a single turn in Find Mii.
61. Broke through a yellow shield in Find Mii.
62. Broke through a light-blue shield in Find Mii.
63. Made it through a dark room in Find Mii.
64. Completed Find Mii.
65. Completed Find Mii twice.
66. Completed Find Mii five times.
67. Completed Find Mii 10 times.
68. Completed Find Mii with 30 or fewer Mii characters.
69. Made it through a dazzling room in Find Mii II.
    
70. Made it through a fiery room in Find Mii II.
71. Made it through an icy room in Find Mii II.
72. Made it through a poisonous room in Find Mii II.
    
73. Broke through a shadowlight shield in Find Mii II.
    
74. Completed Find Mii II.
75. Completed Find Mii II's secret quest.
76. Completed Find Mii II's secret quest twice.
77. Completed Find Mii II's secret quest five times.
78. Completed Find Mii II's secret quest 10 times.

Thanks to NintendoFreak15.