My Raspberry Pico Pico directory is now gathering pace with some useful device drivers.
The most important ones are likely to be: flash example, SSD1306 OLED, and SD Card block reader (no file system support).
Other devices that are likely to be useful: Blinkt, 8×8 Matrix display, and 7-segment displays.
There’s a bunch of other examples and stuff for you to play with, including: RP2040 file for KiCad software, a Forth, a Basic, Picol (small Tcl-like language), a whole bunch of sound stuff (noise generators , PWM examples, filters, frequency generators, bytebeats, a simple drum machine, etc.) , button debouncers, plus an assortment of code to demonstrating the RP2040’s hardware.
Have at it.
Code is here.
Mark Carter's blog 