The minimalist Neopiko marker pad from Deleter is great for quick sketches or practicing with alcohol markers. One side of the paper is coated, making for easy blending, and each sheet is thin enough to use as tracing paper. The B5 size (6.9"x9.8") fits easily into a bag for drawing on the go. In addition to alcohol markers, ink and colored pencils will work well on the super-smooth surface.
Deleter is a brand known for supplying manga artists in Japan with screentones, pens, paper, and more.