They might not be potions, but they certainly do look like them!
HisDarkestFear
Lord
Insider
There have also been potions on and around the Order of Souls characters for quite some time. Maybe there is at least going to be some lore revolving around potions, given their notable presence in the world?
Cyantifical
Lord
Insider
Let's keep our hopes up for them in The Arena! (would make sense being a pvp update and all, but they will affect the game probably more than cursed cannonballs so we'll have to see)
Dreamcrusher401
Commander
Insider
I recall a very old update when the game was new claiming "the only paid DLC in this game would be pets and potions." So I have been expecting them for sometime but there has been no mention on what they do. Perhaps it does have something to do with the arena if it is in fact happening.