Google anything related to Egypt and tombs and the first 10,000 results are likely to center on the discovery of Tutankhamun's tomb in November 1922. Although 62 tombs had been discovered in the Valley of the Kings before then, Tut's was the first tomb that hadn't been completely pilfered throughout antiquity. As a result, it was the first time archaeologists and Egyptologists were able to see what a pharaoh's tomb really looked like.
The documentation of everything related to Tut's tomb is extensive. That makes research extremely easy, but also a field of rabbit holes into which it's easy to fall down (hence at 11 pm I found myself reading wikipedia pages about how Tut's parents weren't Akhenaten and Nefertiti as I'd been taught in school, a fact which still boggles my mind!). Readers interested in the subject will find a plethora of information spanning primary sources, YouTube videos, etc., but for those who want a more tailored study, I found the following really cool websites that I used to educate myself:
Howard Carter's diary: http://www.griffith.ox.ac.uk/gri/4sea1not.html
Colorized photos of the inside of Tut's tomb: https://mashable.com/2015/11/04/king-tut-discovery/
This video of archival footage of the tomb and Carter: https://www.youtube.com/watch?v=7ZWB5-aXMXQ
A nice slideshow with items from the tomb in color: https://slideplayer.com/slide/12954090/
Finally, this YouTube channel has a lot of cool stuff about the tomb, including pictures of the archaeologists and Egyptologists involved: https://www.youtube.com/channel/UCIX7u4u4rfGFCjD2mTpG_eQ/videos
Another tomb mentioned in Chapter 1 is that of Ramses V and VI (the tomb was originally started by Ramses V and then usurped by his successor Ramses VI). The following two sites give wonderful views of the highly detailed and intricate drawings/carvings in that tomb, and provide a sense of its massive scale:
YouTube video with narration: https://www.youtube.com/watch?v=fnqm-XSPe8k
A full 3-D model of the tomb from the Egyptian Tourism Authority: https://my.matterport.com/show/?m=NeiMEZa9d93&mls=1
Finally, brief mention is made of the tomb of Yuya and Tjuyu, the politically powerful parents of the pharaoh Ay and Queen Tiye, wife of the pharaoh Amenhotep III. A brief description of what was found in their tomb can be found at http://anubis4_2000.tripod.com/SpecialExhibits/YuyaTuyu.htm.
In a previous draft, the royal caches were discussed more at length. Here's what was cut: "During the 21st Dynasty, Egypt’s priests had moved dozens of royal mummies whose tombs had been robbed from the Valley of the Kings to Deir al-Bahri. There, a single tomb had become the unceremonious dumping ground for some of Egypt’s greatest pharaohs. By then, all of their funerary trappings—the gold, ebony, precious gems, alabaster and ivory with which they’d been buried—were gone, their gold sarcophagi melted down. The robbers had been so vicious in their plundering they had even torn the wrappings off the mummies, dislocating and destroying limbs and faces as they’d tried to pry off the solid gold amulets that had been wrapped with the bodies to speed the kings to the afterlife. All that was left were bones and dusty linen. This sad cache had been discovered in 1881. Archaeologists hadn’t expected any more to exist. Then a second cache of royal mummies was discovered in the Valley of the Kings in 1898."
Thus when Howard Carter said Tut's tomb could be a cache, there was a very real possibility that what awaited them in the antechamber or burial chamber was a pile of ravaged mummies.