What microcontrollers can utilize 30-52MBit RS-485?
If you are planning to use asynchronous communication (a standard UART) then this will be very difficult. In order to properly detect the beginning to a transmitted data word the serial receiver must have a clock frequency much higher than the data rate, typically 16x higher but you might get away with 8x. So, your 50 Mbit/s data rate will require a UART running at something like 800 MHz. This is far beyond the normal data rate for a UART so it is unlikely that you will find a standard, low-cost device that meets your requirements.

You will probably need a synchronous data stream that either provides a clock on another pair of wires or embeds the clock in the data.