~ I made a really cute polka dot pattern by coloring the end of a pencil eraser with a Crayola marker and stamping it down on cardstock. I also find coloring a rubber stamp with a Crayola marker is a great alternative to buying an ink pad, as you can get it in the small groves.
~ I took an old toothbrush and colored the ends of he bristles with a marker, then dipped the tips lightly in water. Then I used my finger and flicked the bristles, making spatter on my paper. It looked really neat! Careful though, it gets messy, lol.
~ I found an old cork stopper and colored it with a marker and rolled it around on some scrap paper to see what it'd do. It was a bit unpredictable, bu it still looked really neat. Something to try and it has a bit of a learning curve, but worth experimenting with.
Have fun trying stuff out!