I've added to the collection of opening guides a PDF booklet and a PGN file for the Old Indian and Philidor's Defence (one booklet), same again for the Benko Gambit and Cambridge Springs Defence, and PGN+PDF for each the three Black hypermodern defences: Alekhin's, Grunfeld's and the Pirc/Modern complex.  

I think we're pretty well done now; I don't want to tempt anyone with a booklet on any of the hypermodern openings for White or anything less orthodox than I've done already.

Comments invited.

The full list of everything that there is at least a chapter (c) on is as follows:

Albin Counter-Gambit (c) [PGN] [ PDF]
Alekhin's Defence*  [PGN] [PDF]
All Purpose System (...b6 against 1.d4) [PGN] [PDF]
Benko Gambit (c) [PGN] [PDF] / Booklet [PGN] [PDF]
Benonis for Black* [PGN] [PDF]
Cambridge Springs Defence (Queen's Gambit) [PGN] [PDF]
Caro-Kann Defence* [PGN] [PDF]
Colle System [PGN] [PDF]
Colle-Zukertort System [PGN] [PDF]
Danish Gambit [PGN] [PDF]
Dutch Starter repertoire (Italian, French, Tarrasch) [PGN] [PDF]
Dutch Stonewall [PGN] [PDF]
1.e4 systems e.g. Bishop's Opening: Playing Black [PGN] [PDF]
Evans' Gambit (c) [PGN] [PDF]
f4 systems: F for Forward * (Vienna, Grand Prix Attack, etc) [PGN] [PDF]
French Starter repertoire (Italian, French, Tarrasch) [PGN] [PDF]
French Defence* (more detail) [PGN] [PDF]
French Defence: Tarrasch Variation [PGN] [PDF]
Gambit systems: Dial G for Gambit* (King's Gambit etc.) [PGN] [PDF]
Grunfeld Defence* [PGN] [PDF]
IQP systems [PGN] [PDF]
Indian: White Systems with Bg5 (no c4) [PGN] [PDF]
Indian: White Systems with c4 c3/Bg5* [PGN] [PDF]
Italian Starter repertoire (Italian, French, Tarrasch) (c) [PGN] [PDF]
Italian Game [PGN] [PDF]
King's Gambit [PGN] [PDF]
King's Indian Attack [PGN] [PDF]
King's Indian Defence* [PGN] [PDF]
Koltanowski Gambit (c) [PGN] [PDF]
London System* [PGN] [PDF]
Morra Gambit* [PGN ] [PDF]
Nimzo-Indian (& Bogo-Indian)* [PGN] [PDF]
Old Indian Defence [TBD]
Petroff Defence [PGN] [PDF]
Pirc/Modern Defences* [PGN] [PDF]
Queen's Gambit [PGN] [PDF]
Queen's Indian (& Neo-Catalan)* [PGN] [PDF]
Ruy Lopez [PGN] [PDF]
Scandinavian Defence [PGN] [PDF]
Schliemann Gambit (Ruy Lopez) (c) [PGN] [PDF]
Scotch Game [PGN] [PDF]
Scotch Gambit [PGN] [PDF]
Sicilian Defence [PGN] [ PDF]
Sicilian Grand Prix Attack (c) [PGN] [PDF]
Sicilian Wing Gambit (c) [PGN] [PDF]
Sicilian Scheveningen* [PGN] [PDF]
Slav Defence [PGN] [PDF]
Swiss Defence [PGN] [PDF]
Tarrasch Starter repertoire (Italian, French, Tarrasch) (c) [PGN] [PDF]
Tarrasch Defence (more detail) * [PGN] [PDF]
Two Knights' Defence [PGN] [PDF]
Unorthodox openings [PGN] [PDF]
Vienna Gambit (c) [PGN] [PDF] 

* more detailed -- experts only!