I would add 100% chance for:
1. Tanks - random flask, 1-3 portions of relevant food, 2-5 relevant potions, 1-2 uncut and non-yellow gems of rare quality. + Free repair kit (even if you don't die, melee wear-and-tear repair bills are too high), which would repair all your gear at no cost with 1 charge.
2. Healers - random spirit or intellect flask, 1-3 random spirit or intellect food (of best quality) and random 2-5 potions, relevant for their role.
3. DPS - random 2-5 potions, relevant to their spec.
Tanks and healers have higher bonuses, as they need more incentive, and have more problems in farming their own stuff than dps.