Grim Misadventures #3: 5% chance of awesome on hit

I’m wondering how much direct relation there is between skills and affixes. My immediate thought has been ‘affixes with +skill bonuses’ - mostly for single skills, if this is for early (not legendary) items. On a second thought I can image other affixes which increase damage, range, AOE, skill-activation-chance or lower recharge time, energy costs or improve (de-)buffs … ah, maybe too powerful, if they work globally. On a third thought I remembered Affix Skillz. medierra mentioned you might find items with affix skills starting from level 18 - what will be the minimum quality of such items?