Player's Guide to Faerun
The Player's Guide to Faerun was a Dungeons & Dragons 3.5e splatbook that expanded upon some of the material in the 3.0e Forgotten Realms Campaign Setting. It is not a replacement for or upgrade from a previous book like the Expanded Psionics Handbook was. Its most memorable contribution to the game was its variant rules for playing Drow, Duergar, Svirfneblins, and Planetouched without any level adjustment, tucked away on the very last two pages of the appendix. These variant rules became so well-known that they became frequently mistaken for actual distinct races in their own right, and to this day, still show up in fan-made enumerations of playable races in Third Edition. Aside from that, the book was mostly full of fluff and bullshit about the different regions of Faerun and the "Cosmology of Toril", many pages of region-specific feats that no one ever used because no one gave a fuck about Faerun's region system, and the usual amount of prestige classes, magic items, and other crap. No playable races or base classes were included.