go-brute 
A bruteforce combination generator for a specific character set
Example
characterSer := []rune("AB")
minLen := 1
maxLen := 2
b, _ := Brute(characterSer, minLen, maxLen, 4)
for combination := range b {
fmt.Println(combination)
}
// Output:
// A
// B
// AA
// AB
// BA
// BB