Woodgrain effect by randomizing layer temperature in Cura. Suitable for wood filaments.
An implementation of https://www.reddit.com/r/3Dprinting/comments/gp5vrp/randomly_adjusting_the_print_temp_per_layer_gives/
Open your config folder (Help > Show Configuration Folder), and place "Woodgrain.py" in the scripts directory.
Restart Cura
Open the Post Processing window (Extensions > Post Processing > Modify G-Code), select "Add a Script", and select "Woodgrain Effect". Fill out the temperature range and close the window.