Here's something I use, a "random point buy". Roll a d12, and take the corresponding array:
1: 18, 14, 11, 10, 10, 8
2: 18, 13, 13, 10, 10, 8
3: 18, 12, 12, 12, 10, 8
4: 17, 16, 11, 10, 10, 8
5: 17, 15, 13, 10, 10, 8
6: 17, 14, 14, 10, 10, 8
7: 17, 13, 13, 13, 10, 9
8: 16, 16, 13, 11, 10, 8
9...