Let's be very specific...
RF is brand specific, there is no such thing as a 'universal' RF remote that can work with or encode RF frequencies from a dozen different manufacturers. This is a common control issue and something that professional installers are well aware of and help you avoid during an installation, but is not something that can be overcome by purchasing 'the right' remote. There isn't one.
But, if you add a secondary layer of control, like X10, which can actually control your devices, then that may help solve your issues. Yet, this isn't likely to be what you need. More likely is that you simply are stuck with multiple remotes. IR, low-voltage, RS-232 - those are the control methods to use when you need to control devices with remotes. IR is still king because even though it is line-of-site, it is easy to learn, easy to use, and you can run a hard wire and a small IR emitter on the device directly.
Unless your RF gear is X-10 right now, you are not likely going to get anything to control it. It simply is a lousy way to control single devices without IR as a secondary control method.