Shadow of the Tomb Raider

To unlock this achievement, you'll need to complete 9 challenge tombs from the base game. The earliest time you can unlock it is after you have returned from the 'Mission of San Juan' region.
No special gear is needed, you can complete them as soon as you have access to the region. Some parts of the map are locked initially and you'll need to advance the story to get access. I listed the tombs in order they get available.
To reveal tomb locations, talk to the locals, or watch the video under the spoiler tag.

For the video, all credit goes to PowerPyx


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The guide follows this format:

Area
x. Tomb name
Skill reward name - Skill description
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Peruvian Jungle

1. Underworld Gate
Caiman’s Heart – Health regenerates more quickly.

2. Judge’s Gaze
Eagle’s Perch – Increase climbing skills to traverse the environment with more speed.

Kuwaq Yaku

3. Howling Caves
Huracan’s Mantle – Reduce damage from fire and explosions.

The Hidden City

4. Temple of the Sun
Hoatzin’s Hunger – Increase the amount of natural crafting resources gathered from each source.

Cenote

5. San Cordoba
Caiman’s Breath II – Further increase breath capacity when swimming underwater.

The Hidden City

6. Ancient Aqueduct
Jaguar’s Paw – Increase chance to knock enemies down with melee attacks.

Mission of San Juan

7. Tree of Life
Kinich Ahau’s Boon- Health is instantly restored once, when near death in battle. Refreshes between encounters.

8. Thirsty Gods
Sip’s Strike – Charged arrows deal more damage against armored enemies.

The Hidden City

9. Path of Battle
Sip’s Quiver – Loose up to three arrows without pulling from the quiver.