Here is the full list of all 100 OG Puzzlers: Synthwave Monsters achievements.
Monster 1
Monster 2
Monster 3
Monster 4
Monster 5
Monster 6
Monster 7
Monster 8
Monster 9
Monster 10
Monster 11
Monster 12
Monster 13
Monster 14
Monster 15
Monster 16
Monster 17
Monster 18
Monster 19
Monster 20
Monster 21
Monster 22
Monster 23
Monster 24
Monster 25
Monster 26
Monster 27
Monster 28
Monster 29
Monster 30
Monster 31
Monster 32
Monster 33
Monster 34
Monster 35
Monster 36
Monster 37
Monster 38
Monster 39
Monster 40
Monster 41
Monster 42
Monster 43
Monster 44
Monster 45
Monster 46
Monster 47
Monster 48
Monster 49
Monster 50
Monster 51
Monster 52
Monster 53
Monster 54
Monster 55
Monster 56
Monster 57
Monster 58
Monster 59
Monster 60
Monster 61
Monster 62
Monster 63
Monster 64
Monster 65
Monster 66
Monster 67
Monster 68
Monster 69
Monster 70
Monster 71
Monster 72
Monster 73
Monster 74
Monster 75
Monster 76
Monster 77
Monster 78
Monster 79
Monster 80
Monster 81
Monster 82
Monster 83
Monster 84
Monster 85
Monster 86
Monster 87
Monster 88
Monster 89
Monster 90
Monster 91
Monster 92
Monster 93
Monster 94
Monster 95
Monster 96
Monster 97
Monster 98
Monster 99
Monster 100