Here is the full list of all 23 Guardian of Lore achievements worth 1,000 gamerscore.
Enter the Library for the first time.
Save the Yerba Mate Legend
Save Lirolay Flower Legend
Save the legend of Guatavita's Cacique
Save the Coatlicue and Coyolxuahqui Legend
Save the Aya Huma Legend
Save The Virgin and the Cherufe Legend
Save the Merida Snowy Mountains legend
Defeat the Library Guardian without equipping a shield
Lit the bonfire in the YerbaMate Hunter's camp
Get the Huitzilopochtli's Sword
Fall down the Yerba Mate 1B well and die
Defeat the Library Guardian without being hit
Defeat the Corrupted Yaguarete without being hit
Defeat the four eagles in Sierras Nevadas de Merida without being hit
Defeat the Flower of Lirolay Brothers without being hit
Defeat the Coyolxahuqui in the legend of Coatlicue without being hit
Defeat the Guatavita's Golden Colossus without being hit
Defeat the Cherufe without being hit
Save or defeat the single Aya Humas inside their legend without being hit
Save or defeat the two Aya Humas inside their legend without being hit
Defeat the final boss in the game without being hit
Defeat the Cherufe without breaking any of its hands