Key: no stars = common potion, * = uncommon potion, ** = rare potion
As far as I've figured out these are all the existing potions (please correct me if I'm missing any):
Red+Orange+Pink = skinny potion
Red+Orange+Green = small breasts potion
Red+Orange+Cyan = average potion
Red+Orange+Violet = flat breasts potion
Red+Orange+White = chubby potion
Red+Orange+Black = medium breasts potion
Red+Green+Orange = large nipples potion
Red+Green+Pink = large breasts potion
Red+Green+Cyan = huge breasts potion *
Red+Green+Violet = medium nipples potion
Red+Green+White = small nipples potion
Red+Green+Black = bubble butt potion
Red+Violet+Orange = futa potion **
Red+Violet+Green = muscular potion
Red+Violet+Cyan = female potion *
Red+Violet+White = male potion *
Red+Violet+Black = fit potion
Red+Black+Orange = human ears potion
Red+Black+Pink = heart butt potion
Red+Black+Green = pointy ears potion
Red+Black+Cyan = innie vagina potion
Red+Black+Violet = normal vagina potion
Red+Black+White = outie vagina potion
Orange+Red+Black = deep blue skin potion
Orange+Red+Pink = olive skin potion
Orange+Red+Green = light green skin potion
Orange+Red+Cyan = almond skin potion
Orange+Red+Violet = deep green skin potion
Orange+Red+White = chocolate skin potion
Orange+Pink+Black = gold eyes potion
Orange+Pink+Red = brown eyes potion
Orange+Pink+Green = light brown eyes potion
Orange+Pink+Cyan = droopy ears potion
Orange+Pink+Violet = silver eyes potion
Orange+Pink+White = black eyes potion
Orange+Green+Black = face paint 4 potion
Orange+Green+Red = freckles A potion *
Orange+Green+Pink = light blue skin potion
Orange+Green+Cyan = crimson skin potion
Orange+Green+Violet = copper skin potion
Orange+Green+White = cinnamon skin potion
Orange+Cyan+Black = red eyes potion
Orange+Cyan+Red = light blue eyes potion
Orange+Cyan+Pink = green eyes potion
Orange+Cyan+Green = purple eyes potion
Orange+Cyan+Violet = blue eyes potion
Orange+Cyan+White = light green eyes potion
Orange+Violet+Black = fair skin potion
Orange+Violet+Red = ashen skin potion
Orange+Violet+Pink = brown hair potion
Orange+Violet+Green = pale skin potion
Orange+Violet+Cyan = light brown hair potion
Orange+Violet+White = dark blue hair potion
Orange+White+Black = red hair potion
Orange+White+Red = blonde hair potion
Orange+White+Pink = copper eyes potion
Orange+White+Green = auburn hair potion
Orange+White+Cyan = dark hair potion
Orange+White+Violet = silver hair potion
Orange+Black+White = face paint 2 potion
Orange+Black+Red = moles A potion
Orange+Black+Pink = face paint 5 potion
OrangeBlackGreen = moles B potion
Orange+Black+Cyan = face paint 1 potion
Orange+Black+Violet = face paint 3 potion
Green+Red+Violet = swimsuit tan potion
Green+Red+White = petite butt potion
Green+Red+Black = puffy nipples potion
Green+Red+Orange = bikini tan potion
Green+Red+Pink = wide hips potion **
Green+Red+Cyan = narrow waist potion **
Green+Orange+Violet = beady eyes potion
Green+Orange+White = dopey eyes potion
Green+Orange+Black = sly eyes potion
Green+Orange+Red = sharp eyes potion
Green+Orange+Pink = spotty skin potion
Green+Orange+Cyan = fuzzy brows potion
Green+Pink+Violet = eye scars potion
Green+Pink+White = cheek scars potion
Green+Pink+Black = pretty mouth potion
Green+Pink+Red = pretty brows potion
Green+Pink+Orange = pretty eyes potion
Green+Pink+Cyan = moles C potion
Green+Cyan+Violet = short ponytail potion
Green+Cyan+White = long ponytail potion
Green+Cyan+Black = short bob potion
Green+Cyan+Red = sideswept ponytail potion
Green+Cyan+Orange = mush bob potion
Green+Cyan+Pink = medium bob potion
Green+Violet+Cyan = shaved potion
Green+Violet+White = fiend horns potion **
Green+Violet+Black = black sclera potion *
Green+Violet+Red = fiend tail potion **
Green+Violet+Orange = white sclera potion
Green+Violet+Pink = messy strip potion
Green+White+Cyan = bun and bangs potion
Green+White+Violet = double bun potion
Green+White+Black = small strip potion
Green+White+Red = heart shave potion
Green+White+Orange = strip shave potion
Green+White+Pink = sideswept potion
Green+Black+Cyan = underbite potion
Green+Black+Violet = slickback potion
Green+Black+White = average butt potion
Green+Black+Red = undercut potion
Green+Black+Orange = buzzcut potion
Green+Black+Pink = fangs potion **
Black+Red+White = firm buttcheeks potion
Black+Red+Orange = imp horns potion **
Black+Red+Pink = big butt potion
Black+Red+Green = pink hair potion
Black+Red+Cyan = beefy butt potion
Black+Red+Violet = soft buttcheeks potion
Black+Orange+White = coral hair potion
Black+Orange+Red = perky breasts potion
Black+Orange+Pink = cyan hair potion
Black+Orange+Green = bolt on breasts potion
Black+Orange+Cyan = light green hair potion
Black+Orange+Violet = violet hair potion
Black+Pink+White = deeper voice potion
Black+Pink+Red = soft voice potion
Black+Pink+Orange = high voice potion
Black+Pink+Green = average penis potion
Black+Pink+Cyan = hobgoblin horns potion **
Black+Pink+Violet = deep voice potion
Black+Green+White = shortstack potion
Black+Green+Red = slender potion *
Black+Green+Orange = built potion *
Black+Green+Pink = saggy breasts potion
Black+Green+Cyan = petite potion *
Black+Green+Violet = broad shoulders potion
Black+Cyan+White = tiny penis potion
Black+Cyan+Red = zombified skin potion
Black+Cyan+Orange = grey eyes potion
Black+Cyan+Pink = small penis potion
Black+Cyan+Green = bloodshot sclera potion
Black+Cyan+Violet = hairy potion
Black+Violet+White = huge butt potion
Black+Violet+Red = round butt potion
Black+Violet+Orange = fit butt potion
Black+Violet+Pink = tiny nose potion
Black+Violet+Green = wide butt potion
Black+Violet+Cyan = large nose potion
Black+White+Violet = chubby face potion
Black+White+Red = round face potion
Black+White+Orange = gaunt face potion
Black+White+Pink = zombie mouth potion
Black+White+Green = normal face potion
Black+White+Cyan = square face potion