Funky Fluids is a mod that adds various fluids with interesting and weird properties.
This is a list of all the fluids it adds:

Oobleck

A non-newtonian fluid that increases in viscosity the more force you
apply to it. If you approach it slowly, it will behave as a liquid, but
if you impact it with a lot of force, it will behave as a solid. This
means that you can run and jump on it without sinking into it.

Liquid Crystal

It flows like a liquid but it behaves like a solid when you touch it. This means that you can stand on it.

Melonade

A delicious drink made of watermelon and sugar.

Silly Putty

Similar to oobleck but it's also bouncy, which is of course an improvement.

Redstone Suspension

A suspension of redstone in water, it emits a constant redstone signal with the strength depending on the level of the fluid.

Magnetroleum

A liquid that pulls entities in the opposite direction of the flow, essentially pulling them towards the source block.