Discworld (1995) came with an actual t-shirt in the box. But there was an insane period in the early 2000s where they'd stopped doing manuals, maps and other extras but still packaged the disc in a box the size of a 450g cornflakes packet.

I'm ok with manuals not being a thing, because it's a reflection of improvements in both software and game design where you don't need to read 24 pages of text before you can play a game. But I'm not ok with publishers basically killing the secondary market.