This is a (hopefully) complete list of the handguns used by the Wehrmacht, compiled by Forum members varjag, The Edge and Sitzkrieg.

Germany
Gustloff Pistole .32ACP
Mauser M. 1934 .32ACP
Mauser HSc .32 and .380ACP
Mauser C/96 7,63mm and 9mm Mauser & 9mm Parabellum
Mauser 712 7,63mm Mauser
Pistole 08 (Luger) 9mm Parabellum
Reichsrevolver M/79 & 83 10,6mm Reichsrevolver
Sauer M. 1930 .32ACP
Sauer 38H .32ACP
Volkspistole (Gustloffwerke) 9mm Parabellum
Volkspistole (Mauserwerke) 9mm Parabellum
Volkspistole (Walther) 9mm Parabellum
Walther PP .32 and .380ACP
Walther PPK .32 and .380ACP
Walther P.38 7,65 and 9mm Parabellum
Austrian
Steyr Pistole 34 (Model 1908) .32ACP
Steyr Pistole M.12 (ö) 9mm Steyr and 9mm Parabellum
Steyr Pistole M.12/P 16 9mm Steyr
Czechoslovakian
Pistole 24(t) CZ Model 1924 .380ACP
Pistole 27(t) CZ Model 1927 .32ACP
Pistole 39(t) CZ vz.38 380ACP
? CZ Model 36 .25ACP
French
Unique Model 16 & 17 .32ACP
Unique Model ‘D” .32ACP
MAB Model ‘A’ .32ACP
MAB Model ‘D’ .32ACP
Hungarian
Pistole 37(u) Femaru M.1937 .32 and .380ACP
Polish
Pistole 35(p) [also as Pistole 645(p)] 9mm Parabellum
Spanish
ASTRA 200 .25ACP
ASTRA 300 .32 and .380ACP
ASTRA 400 9mm Largo
ASTRA 600 9mm Parabellum
ASTRA 900 7,63mm Mauser
Echeverria SA ‘Star’ Model B 9mm Parabellum

Foreign equipment, so called ’Fremdgeräte’
The letters in brackets denote the country from which obtained, not made.
(a) USA, (b) Belgium, (d) Denmark, (e) Britain, (f) France, (g) Greece, (h) Netherlands, (i)Italy,(j) Yugoslavia, (n) Norway, (p) Poland, (r) Soviet Union, (ö) Austria
These sidearms were classified by the Waffen-Amt (Ordnance Office) but not neccessarily used by the Germans.
Revolver 610(n) Norwegian Nagant M. 1893 7,5mm Nagant
Revolver 612(p) Polish Nagant M. 1895 7,62mm Nagant
Revolver 612(r) Russian Nagant M. 1895 7,62mm Nagant
Revolver 612(g) Greek Nagant M.1895 7,62mm Nagant
Revolver 613(g) Greek Nagant M. 1912 7,62mm Nagant
Pistole 615 (r) Soviet TT 30/33 7,62mm Tokarev
Pistole 620(b) FN Model 1900 .32ACP
Pistole 621(b) FN Model 1910 .32ACP
Pistole 622(b) Colt Pocket Model 1903 .32ACP
Pistole 623(f) Echeverria ‘Star’ Model 1914 .32ACP
Pistole 624(f) Gabilondo ‘Ruby’ M.1915 *) .32ACP
Pistole 625(f) MAS Model 35A 7,65mm French Longue
Pistole 626(b) FN Model 10/22 .32ACP
Pistole 626(d) FN Model 1922 .32ACP
Pistole 626(h) FN Model 10/22 .32ACP
Revolver 634(f) Orbea Hermanos, copy Smith & Wesson Military & Police **) 8mm Lebel
Revolver 635(f) not identified Smith & Wesson copy 8mm Lebel
Revolver 636(f) Garate Anitua, copy of Colt New Service Revolver ***) 8mm Lebel
Revolver 637(f) French Service revolver M.1892 8mm Lebel
Pistole 640(b) FN HP 1935 9mm Parabellum
Pistole 641(b) FN Model 10/22 .380ACP
Pistole 641(h) FN Model 10/22 .380ACP
Pistole 641(j) FN Model 10/22 .380ACP
Pistole 642(f) ASTRA Model 1921 9mm Largo
Revolver 643(h) Dutch Service Revolver M.1912 9,4mm Dutch Service
Pistole 644(d) Danish Bergmann-Bayard M.10/21 9mm Bergmann
Pistole 645(p) Polish VIZ wz35 9mm Parabellum
Revolver 646(e) British Enfield No.2 Mk 1 .38/200
Pistole 647(f) Echeverria ‘Star’ Model A 9mm Largo
Revolver 648(g) Colt Army Special M. 1908 .38 Special
Revolver 649(g) Smith & Wesson Military & Police .38 Special
Revolver 654(f) French Chamelot-Delvigne M.1873/74 11 mm French
Revolver 655(e) British Webley No.1 Mk VI .455 Webley revolver
Pistole 657(n) Norwegian Kongsberg-Colt M. 1912/14 11,25mm Norwegian
Pistole 660(a) Colt M. 1911 automatic .45ACP
Revolver 661(a) Colt M. 1917 .45ACP
Revolver 662(a) Smith & Wesson M. 1917 .45ACP
Pistole 670(i) Glisenti/Brixia M.1910 9mm Glisenti
Pistole 671(i) Beretta M. 1934 .380ACP
Revolver 680(i) Italian Bodeo M. 1889 10,35mm Bodeo

*) ’Ruby’ pistols were made by some 30 different manufacturers and sub-contractors. Magazine-capacity varies between seven, eight and nine rounds. Exported to France 1915-1918.
**) Smith & Wesson Military & Police revolvers were copied by several Spanish Manufacturers and exported to France 1915-18. It is unclear how the revolvers differed between different manufacturers but they were mostly minor. For that reason is has not been possible to positively identify  ‘Revolver 635(f)’.
***) A similar story pertains to the Colt revolver copies exported to France 1914-18. They may have shown more discrepancies between various manufacturers than the Smith & Wesson revolvers.
All Spanish revolvers imported to France during World War One, were collectively known as Mle  92 Espagnol (Model 92 Spanish) after the Model 1892 French service revolver with which they shared caliber.