Tony Goodhew has written up a great Instructable to help you get the most out of the Pimoroni Pico Explorer using the Pimoroni MicroPython firmware.

He uses the screen to do various drawing exercises at a low level (circles, squares, that sort of thing) and also some mathematical function rendering. He finishes off by taking a potentiometer and an LED, using them in combination with PWM to create a dimmable lamp with a graphical readout of the pot level on the screen. You can take a look at the Instructable here.