Acrylic Mediums alter acrylic paint in all sorts of interesting ways. Pouring Medium, for instance, allows the paint to flow so it can be poured onto surfaces, and dry without cracking. I used this medium to make Halloween Skins, Pumpkin Decorations, and some Gerhard Richter inspired paintings.
Another medium, Glass Beads Gel, adds a glossy, bead-like texture to your work, and can be mixed with acrylics or added on top. This medium added a perfect finish for Painting A Galaxy, and a fun texture to Puzzle Piece Pins.
Recently, I picked up some Acrylic Gel Medium which not only alters the texture of acrylic paint, but enables you to transfer printed images onto other surfaces, making it ideal for creating layers in collages and mixed media. In this instance, I simply used it as an adhesive to transfer images onto a box and future pencil holder. It turned out to be super easy to work with.