AD&D 2E "Lite" for Free via Beamdog Game Manuals

Want quick and free access to a light version of AD&D 2e rules and a few free gazetteers of the Forgotten Realms? Gotcha covered! Just download the following game manuals available on the websites for the enhanced editions of Beamdog's Baldur's Gate series of AD&D PC Games:

Baldur's Gate Enhanced Edition
Adventurer's Guide - Contains all the rules you need to play

Sword Coast Survival Guide - Gazetteer of the Sword Coast

Baldur's Gate II Enhanced Edition
Amn Survival Guide - Gazeteer of Amn

Mastering Melee & Magic - Contains all the rules you need to play

Icewind Dale Enhanced Edition
Feature Guide - The actual game manual; skip it if you don't need an overview of the cRPG

Survival Guide  - Gazetteer of the Icewind Dale settings

Mastering Melee & Magic - Contains all the rules you need to play

Baldur's Gate: Siege of Dragonspear
Adventurer's Guide - Same file as listed under BGEE, above

Survival Guide - Same file as the Sword Coast Survival Guide, above

Field Report - Gazetteer of the Dragonspear setting

UPDATE on 2019-08-29:
I found links to some Atari D&D game manuals on the Atari's FTP server and the Neverwinter Vault, a fan forum for modders of the game. These rules use the D&D 3rd Edition rules.

Neverwinter Nights Enhanced Edition
Game Manual (basically a cleaned-up scan of the Diamond Edition manual)

Neverwinter Nights
Game Manual & Online Manual (these are the same file with different names)

Neverwinter Nights Diamond Edition Manuals

Hordes of the Underdark Expansion Manual

Shadows of Undrentide Expansion Manual

Neverwinter Nights Platinum Game Manual

Neverwinter Nights 2
Game Manual (best quality)

Mask of the Betrayer Expansion Pack Manual

Temple of Elemental Evil (uses D&D 3.5 Edition rules)
Game Manual