You know how November is NaNoWriMo and October is Inktober? Well a bunch of level designers are doing their own thing with the hashtag #Blocktober, showcasing level creation with early blockouts of games at different stages of development.
A lot of them are from designers who worked on the Uncharted series, so there are a lot of cool images showing Uncharted games without their clothes on, so to speak, including parts of The Lost Legacy, different iterations of Uncharted 3's Chateau level, this great one of the clock tower in Uncharted 4, and Nate's island arrival in the same.
Then you've got some that have a little more texture filled in, like these of Echo 11 from Star Citizen, and these comparisons showing how areas of colour make the level easier to read than when it's blocked in grey. These shots of an in-progess WarGames from Titanfall even show an area that was cut from the level in the full game.
Blocktober is not only super fun and interesting for anyone outside game dev, but also if you're looking to get into it. There are students sharing their projects, teachers sharing blockouts they've done for classes, and loads of maps from stuff like TF2, and early iterations of Hob and Homefront. Get involved.