I remember getting excited about finding a scroll of Blur at the beginning of Eye of the Beholder II.

I had never encountered that spell before in a Gold Box game.

IIRC there were certain items and possibly spells which one could transfer across from earlier games, which couldn't be aquired in later games.

I think some best in slot items could only be aquired by looting the dead bodies of particular NPC's, or by transferring from earlier games.

Also, some Magic-User spells may have only been available via level ups and not through scribed scrolls found throughout a game.

There were also various bugs to keep track of.

I recall losing entire campaigns from Pool of Radiance>Curse of the Azure Bonds>Hillsfar>Secret of the Silver Blades>Pools of Darkness to disk corruption errors on the Amiga in the early 90's.

Thank f*ck for modern emulation.