There's also this: http://www.scanpyramids.org/ - they found a hidden chamber above the king's but didn't get permission to open it.

There was a video a while ago about geoconcrete. Theory is that they didn't mine sandstone blocks, but rather they built the blocks on site from a form of concrete. The convincing evidence is a block of stone that has a wooden beam coming out of it without any visible holes. It wasn't carved, but cast from a form.

https://piped.kavin.rocks/watch?v=KMAtkjy_YK4

Also air tunnels that are much narrower than a person can fit and a whole lot of other stuff.

Some of it is a bit far fetched, like melting of hard stones, but it may have some truth.