You can tip a potion of levitation onto the ground, which in addition to its normal vapor effects, causes any objects buried there to float to the surface.

Not specified on if this would have an effect when over a liquid; perhaps the items would temporarily float to the surface and immediately sink back down.

Any item can be dipped into a potion of levitation to permanently reduce its weight by 20%. This uses up the potion, and it will only affect the item’s base weight, not the weight of any contents (i.e. a bag of holding thus dipped will weigh 12 + contents instead of 15 + contents). If the object is canceled at a later point, it loses this property and reverts to its normal weight.

The effect cannot be stacked; attempting to dip an already-levitated object into another levitation potion will have no effect and will not use up the potion.

A possible variation is to also confer this effect for potions of enlightenment, since “enlightening” the item could be interpreted as making it physically lighter.

Dipping low boots into a potion of levitation turns them into levitation boots.

Levitation from a blessed potion or an artifact allows you to use < and > to float into the air and descend at will, without the levitation timing out. This would require implementing two additional flags: one that tracks whether your levitation comes from those sources, and one that tracks whether levitation is currently suppressed due to your voluntary descending.

The potion of levitation has negative weight, and lightens your inventory load rather than weighing it down more.

Expert-cast levitation, or a blessed potion of levitation, grants flight instead of levitation.