USB Macro Keys

Hello everyone! I am looking for a USB device that has keys I can macro certain functions and inputs on. One reason I want to get something like this is for Photoshop on my Surface Pro. I like to use most of the screen for actually drawing, and it is inconvenient for me to have my key board in front of me while doing so, so I would like to have a key set to the command Ctrl (+)+ so I can zoom in or out without having to move over to my whole key board and input the command manually. This is just one example of how it would be useful. If there is anything like this out there please let me know, and maybe some recommendation. Thank!