Two come immediately to mind, both PC games: Heroes of Might and Magic II and The Elder Scrolls III: Morrowind
HoMM2 had a big, thick manual explaining all the game mechanics, but the really cool thing was a big inflatable, laminated chart/poster showing you every unit in the game with its stats so you could look stuff up during a battle and make intelligent decisions (I believe the GoG version comes with a PDF of it, but I still have my original physical one and it's awesome).
Similarly, Morrowind came with a gorgeous, full color world map along with the manual. They reprinted it and included it with the anniversary anthology pack that came out in the 2010s that included Elder Scrolls 1 through 5, but they cheaped out and printed it in monochrome.
Bonus: Even the original Pokemon games fit this bill. The manual tells you about the type system and gives you a little rock paper scissors style diagram showing how the 3 starter types beat each other to get you going and hint that other types also interact that way.




