My Studio Calico wood veneer shapes. I've snaffled quite a few over the last few weeks and I love them.
The $1 Thickers I scored from Big Lots this weekend! I haven't put the away yet. I like to pick them up and look at them :). And as an aside, I like Lisa's word above, "snaffled." :)
although it is on the desk in our study rather than my craft desk, my favourite scrappy thing is totally my Silhouette machine. I cannot imagine ever, ever getting tired of that thing!
Probably twine &/or buttons. I usually have a bit of each on my desk, and they're handy to add to any project.