I use an array plus bonuses of +1, +2, and +3 that can each be assigned to any one ability score, with no more than one bonus applied to any score.
So, start with 8, 10, 12, 13, 14, 15. Adding the bonuses could get you:
10, 10, 12, 13, 17, 16
8, 10, 12, 14, 16, 18
8, 10, 12, 16, 16, 16
10...