You didn't say which Roku device you have, so I can't suggest a single device that I am confident will work. So, weed through this.
If it's a Stick, you need a Roku remote that will work with a Stick. The Voice Remote and the Enhanced Voice Remote, as well as the Voice Remote Pro, will all work on Sticks. You can find those on the Roku Website, or can quickly get one from Walmart, Best Buy, Target, and such.
If it's a set top box that you have, it may (or may not, depends on the Roku model) support the same remotes listed above. Set top boxes also support the Simple Remote, which you can get from Roku, or from Walmart, Best Buy, etc. You could also get a universal remote as long as it lists Roku as a supported device.
If it's a Roku TV, you'll need a remote that works with Roku TV. The same remotes that work with the Sticks works with Roku TVs. However, the standard IR remotes (Simple Remote) won't work. You'll need to ensure that a universal remote specifically states Roku TV and not simply Roku.
DBDukes http://www.dbdukes.com/ Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution." Note: I am not a Roku employee.