I would like to help with the effort to save the handbooks from the old boards, I went through the pages and looked for anything that hasn't been moved over.
Here is the list that I collected. If I get permission to be a handbook writer, I can assist in posting these handbooks. Though some of these handbooks are done by current posters, so out of respect, I would not post their work, unless they were alright with it.
fear handbook [caedrus]
Charlatan HB [Shigure]
war compendium [Talore]
Cursed Items Mini-Handbook [Akalsaris]
The Armor & Weaponry Handbook [Daniel678]
The Mole Handbook [snakeman830]
A Guide to Proper Scouting [JaronK]
A Guide to Quickened Progression and Dual Casting [Thrallherd]
Optimization Resource: Trap-Finding [Akalsaris]
Metamagic and You: A Thesis [RelentlessImp]
Making opponents flat-footed (Iaijutsu Strike resource) [BruceLeeroy]
Getting the most out of your familiar [phaedrusxy]
The Guide to Sovereign Speakers and Other Domain Users [rhig]
Caster Level Loops And You [bauglir]
The Gish Handbook [raith0]
Zeroficers - A guide to making tier 0 Artificers [borg286]
Use this or That: A Quick Guide to Alternatives [snakeman830]
The New, Virtually No-Nonsense Guide To Psions [Saeomon]
Soulborn Handbook [Mudkipz]
The Familiars' Handbook [Dictum Mortuum]
Playing Raistlin : Kell's Guide to Playing With Space, Time, and Actions [KellKheraptis]
wish HB [Arniha]
The Fiendbinder Handbook [Ramaloke]
The Healer's Handbook [3.5 Class from the Miniatures' Handbook] [Akalsaris]
Anti-Antimagic: How to cast in an area where magic won't normally function! [Endarire]
Ascetic Rogue Mini-Hanbook [dictum mortuum]
The Dungeon Master's Handbook [Caedrus]
Collection of Necromatic Oddities [Snizor]
Ability Damage Resource by Empirate [Empirate]
Affiliations and Magical Locations Handbook [Jedda]
How To Become Enormous (Meet Mr. Gigantic) [Barbarossa]
Summoning Handbook [chaos_redefined]
Tleilaxu_Ghola's Innovating Party Design: Method and Application [dictum mortuum]
Mini-Guide to Stealthy Characters [shiki]
the ultimate magus handbook [Phoenix00, reposted korwin]
Greenbound SNA Summoning List: "It ain't easy bein' green!" [endarire]
The Opposed Checks Handbook [garryl]
The Utility Belt; or what you should be wearing around your waist [dark_samurai]
Thrallherd Handbook [bigwig]
Sword and Sorcery : The 3.5 Gish [KellKheraptis]