Potion of Levitation

The specific substance that allows shulker bullets to cause any object or player they hit to levitate took many years to isolate, and not just because the shulker itself is almost impossible to study whilst alive. It may be that the substance originates in the body of the shulker, but there is no concrete proof of that yet. All current and past extractions have come from the shells of the shulkers, which suggests that this substance can and is secreted into the shells. This has made experiments to create levitation potions easier, and progress has been more fruitful. Current research has produced potions that can allow the drinker to float up several blocks at a slow pace. Working on the concentrations to produce stronger, more persistent effects is what I'm working on now, and the results are promising.

Potion of Glowing

Conversely, the substance that makes glowberries glow was comparatively easier to extract and turn into potions. Indeed, I might say it's a little too easy. They're simple to farm in mass quantities, and creating a substance capable of producing potions is not difficult at all. Crushing and boiling the juice with sugar and a splash of glow squid ink does the trick. I don't think the glow squid ink is what makes it glow? It does seem to add enough thickness to the syrup for the glow to work as a potion. That's my theory at least. As for its uses, I find it's more interesting with tipped arrows, as it gives thinks hit with it a glowing effect the way spectral arrows do, but that glow can also be dyed. It does work as a drunk potion too, especially as a splash potion. If spectral arrows are are unavailable or not useful, then this is the way to go, especially if you don't want to hurt mobs that need to glow, and it works on everything unlike bells. But I'm sure there's other uses I haven't thought of yet.