So many things in that book that I loved, but gadzooks, was there some stinky broken cheese in there as well!
Drow as a PC race. It was indeed a herald of the Drizztpocalypse. If only they'd followed through on the Drow/Duergar/Svirfneblin trope and made a race of underdark Halflings or Humans with inexplicable magical powers for no darn reason!
Our Illusionist used Chromatic Orb during the Bloodstone modules to kill the Tarrasque. That's how broken it was.
Firewater. Precipitation. Ah, strange spells, how I miss thee! (Not as much as some of the 2e Tome of Magic spells like Metamorphose Liquids 'though...)
Charts of unpronounceable polearms that nobody ever used, how I miss mocking thee!