In this Makefile, you can find all the triggers chosen for a 5.4 kernel.
But I noticed that by
cat /sys/devices/platform/leds/leds/led0/trigger, some triggers are not listed (e.g. "pattern" and "activity").
It turned out that they are compiled as kernel modules but not loaded by default.
They are located under
/lib/modules/[your kernel release]/kernel/drivers/leds/trigger, and you can find out your kernel release by
Then you can either manually load the triggers by
sudo modprobe ledtrig_xxx or add them to
/etc/modules-load.d/xxx.conf to load automatically during boot time.
cat /sys/devices/platform/leds/leds/led0/trigger again and play with the triggers :)