I am working on a game where head is 1TB. On top of code and assets this size includes a few full builds and a full set of game-ready data (the data build process takes something ridiculous like 7 hours, so that's done on a server and it checks the result in). All in the same repository.

1TB is rather a lot. My previous record was 300GB and even that seemed a bit much. But it is very convenient having everything in one place, including all the stuff that you only need occasionally but is handy to have to hand, such as old builds of the game that you can just run in situ and installers for all the tools.

(I don't know what the entire repository size must be like, but many of the larger files have a limited history depth, so it's probably less than 5-10TB. So not exactly unimaginable, though I'm sure buying that much server-grade disk space - doubtless in duplicate - might cost more than I think.)