That is a custom drawer by Wood-Mode; however a previous Houzz user (swamp) mentioned Ikea having dividers that look similar to those. You might try that.

Swamp, does Ikea have truly adjustable dividers? When I looked for something there to put in one of my lower drawers, I could only find ones that just fit in their drawers, which are a different size than my custom cabinets, or had to be attached with screws, which I didn't want to commit to. The ones that say they're adjustable are only so as to moving them front to back but still only fit in drawers that are exactly the width of Ikea's.