Colordrippers by Brian Moss are amazing kinetic liquid toys that let you view fluid dynamics as minutes go by. They are available in a wide variety of colors. The Ferrodrippers take it to the next level with magnetic dust. You can adjust the movement with a strong magnet.
These are handfilled using household fluids for the most part. The above video gives you a better idea what makes these special. You can find the complete collection on BrianMossArt Etsy page.