Baud rates can be just about any value within reason. The only requirement is that both devices operate at the same rate. One of the more common baud rates, especially for simple stuff where speed isn’t critical, is 9600 bps. Other “standard” baud are 1200, 2400, 4800, 19200, 38400, 57600, and 115200.
The higher a baud rate goes, the faster data is sent/received, but there are limits to how fast data can be transferred. You usually won’t see speeds exceeding 115200 - that’s fast for most microcontrollers. Get too high, and you’ll begin to see errors on the receiving end, as clocks and sampling periods just can’t keep up.