Runes!

this look cool but tbh I would never wanted to actually use this pack, the vanilla potions have already confused me enough

I quite like this, but I think personally that it would be better if you did it in a manner that allowed for some differentiation between the different runes, as it's pretty hard for me to tell the difference.
Perhaps you can take inspiration from the icons that appear in the top right when you consume a potion, for example a regeneration potion will have the vague shape of a heart, with poison and harming having the same shape, but with a different colour as they all effect the same thing.
and then as another example, a slow falling could be a vague feather or something similar, so you can see what the potion is without having to guess.
Other than that it's an amazing pack!

I cannot download it because it is a rar file and not a zip file :(

This actually looks pretty cool. Going to do it without optifine and see what happens <3