If you've got the Modesty board, you have to have a few of these. I used mine for attaching my SSD's to, meaning I can keep them off the table top and out of sight, but easily accessible still.

This little product is stronger than it looks. It attaches right to the accessory board that comes with the desk and two come with purchase. I use one of them to hold a six outlet power strip and one to hold my macbook power charger and both have held steady for the past several weeks, even when my kids have knocked up against the desk or I'm adjusting it up or down! For me, this desk/accessories is worth it for the ability to seamlessly hide all my wires/chargers alone.