Leftovers: 1/16 of your total HP.
Aqua-ring: 1/16 your total HP
Leech-seed: This gives you 1/8 of your opponent's HP, so it may be more or less then 1/8th of your HP.
Ingrain: 1/16 of your total HP
Rain-dish/Ice-body: 1/16 of your total HP
*Note: Dry Skin heals 1/8th of total HP.
That totals to be aproximatly 3/8 of your HP healed each turn (give or take because of leech seed). With Dry Skin as the ability, it could be 7/16ths HP restored.