SSD1306 OLED Display
SSD1306 OLED displays are one of the most common in mechanical keyboard kits. They're often used to display information about your keyboard, such as which layer is active, or if any modifiers like Caps Lock, Num Lock or Scroll Lock are on. Of course, you can display anything you want, including images!
These displays work over I2C and should be powered with 5V. They are compatible with Pro Micro-based kits.