Mouse jiggler with speed control of the rotation, and only visible as mouse if boot.py is selected.

boot.py

import storage, usb_cdc
import board, digitalio
import usb_hid, usb_midi

# On the Macropad, pressing a key grounds it. You need to set a pull-up.
# If not pressed, the key will be at +V (due to the pull-up).
button = digitalio.DigitalInOut(board.KEY12)
button.pull = digitalio.Pull.UP

# Disable devices only if button is not pressed.
if button.value:
    storage.disable_usb_drive()
    print("storage.disable_usb_drive()")
    usb_cdc.disable()
    print("usb_cdc.disable()")
    usb_midi.disable()
    print("usb_midi.disable()")
#    usb_hid.enable()
#    print("usb_hid.enable()")
    usb_hid.enable((usb_hid.Device.MOUSE,))       # Enable just MOUSE.
    print("usb_hid.enable((usb_hid.Device.MOUSE,))")

print("End of boot.py")

code.py

# Adafruit Macropad, rotating mouse
# From: https://github.com/todbot/circuitpython-tricks
# Detect if USB is connected or not
import supervisor
import time
import board
import digitalio
import usb_hid
from adafruit_hid.mouse import Mouse

import rotaryio

from digitalio import DigitalInOut,Pull

led = DigitalInOut(board.LED)
led.switch_to_output()

led.value = False

# In practice need 0.8 s before connection
for i in range(10):
  if supervisor.runtime.usb_connected:
    led.value = True   # USB
    print("Connected")
  else:
    led.value = False  # no USB
    print("NOT Connected")
  time.sleep(0.2)  # Debounce delay
print("---------")

for i in range(10):
  led.value = not led.value
  time.sleep(1)

# SPDX-FileCopyrightText: 2018 Kattni Rembor for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""CircuitPython Essentials HID Mouse example"""

mouse = Mouse(usb_hid.devices)

select = digitalio.DigitalInOut(board.BUTTON)
select.direction = digitalio.Direction.INPUT
select.pull = digitalio.Pull.UP

encoder = rotaryio.IncrementalEncoder(board.ENCODER_A, board.ENCODER_B) # must be consecutive on Pico

# Method #7:  Using the iter function and the next function
# From: https://www.geeksforgeeks.org/iterate-over-a-list-in-python/
list = [(0,1), (1,1), (1,0), (1,-1), (0,-1), (-1,-1), (-1,0), (-1,1)]

# Use the next function to retrieve the elements of the iterator
while True:
# Create an iterator object using the iter function
    iterator = iter(list)
    try:
        while True:
            element = next(iterator)
            led.value = not select.value
        #    print(encoder.position)  # starts at zero, goes neg or pos
            mouse.move(x=encoder.position*element[0],y=encoder.position*element[1])
            if select.value is False:
                mouse.click(Mouse.LEFT_BUTTON)
            time.sleep(0.2)  # Debounce delay
    except StopIteration:
        pass