What are the most uncommon songs?

Tianyi Luo's songs are almost all rare words.

For example; Zhen Ji's three thousand crows killed all the immortals and burned fireworks at night.

There are several good songs;

For example; Be the flower of your own heroic battlefield 66-CCFF, etc.

There are also those who learn quickly and hard;

For example; Feeding song: ode to the Millennium cookbook

Attention; Canon seventeen constellations buried flowers