I am unaware of any such remote from Roku themselves. However, all Roku TVs will work with an IR remote, and many such remotes are available with Roku codes.
Here's one from Amazon that is only $9. I don't see Roku or TCL listed on the device list, but Vizio is there and and my Vizio remotes will also control my Sharp Roku TV.
Here's another one that does list Roku and it's just a hair over $10.
But for these generic remotes remember that many of the buttons won't do anything on a Roku device. Such as the direct access channel button (0-9 buttons). You can only move up/down one channel at a time on a Roku TV. They also don't have Roku specific buttons, like the Home, Play, FF, rewind, etc. Probably the most important thing is the directional pad, because that's needed to move around on the Roku home page. Neither of the ones I listed above appear to have such buttons. Perhaps when using a Roku some of the other buttons will replicate those buttons, but without trying it I have no idea personally.
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.