I too am looking for Zenith the Albino, he hasn't appeared in the pulp section yet. Heres a list of his stories taken from
http://www.reocities.com/jessnevins/zenith.html"A Duel to the Death," 25 Oct 1919, Union Jack Library #837.
"The Tenth Case," 29 Nov 1919, Union Jack Library #842.
"The Case of the Man in Motley," 13 Dec 1919, Union Jack Library #844.
"The League of the Cobbler's Last." 3 Jan 1920, Union Jack Library #847.
"The Beggars' Hotel, " 27 Mar 1920, Union Jack Library #856.
"The Five Clues," 6 Mar 1920, Union Jack Library #867.
"The Case of the Four Statues," 12 Jun 1920, Union Jack Library #871.
"The Death Spider," 17 Jul 1920, Union Jack Library #875.
"The Case of the Crystal Gazer," 23 Oct 1920, Union Jack Library #889.
"The Strange Case of the Elsingham Legend," 27 Nov 1920, Union Jack Library #894.
"The Case of the Toxic Tulips," 25 Dec 1920, Union Jack Library #898.
"The Roumanian Envoy," Jan 1921, The Sexton Blake Library (First Series) #156.
"The Thirteenth Bowl," 21 May 1921, Union Jack Library #919
"The Return of Zenith the Albino," 23 Jul 1921, Union Jack Library #928.
"The Corner in Quinine," 24 Sep 1921, Union Jack Library #937.
"The Case of the Five L's," 21 Jan 1922, Union Jack Library #954.
"Threatened By Three," 4 Feb 1922, Union Jack Library #956.
"The Affair of the Sacred Fire," 15 Apr 1922, Union Jack Library #966.
"In League Against Him," 6 May 1922, Union Jack Library #969.
"The Case of the Atwell Aircraft Factory," 11 Nov 1922, Union Jack Library #996.
"The Albino's Double," 14 Nov 1922, The Sexton Blake Library (First Series) #255.
"The Thousandth Chance," 9 Dec 1922, Union Jack Library #1000.
"On Secret Service," 10 Mar 1923, Union Jack Library #1013.
"The Case of the Crimson Curtain," 12 May 1923, Union Jack Library #1022.
"Plague," 2 Jun 1923, Union Jack Library #1025.
"X-Ine," 1 Sep 1923, Union Jack Library #1038.
"The Living Mask, or, Zenith's Masquerade!" 13 Oct 1923, Union Jack Library #1044.
"The Train of Tragedy," 8 Mar 1924, Union Jack Library #1065.
"The Strange Case of the Jig-Saw Puzzle," 5 Jul 1924, Union Jack Library #1082.
"The Man in Steel," 6 Sep 1924, Union Jack Library #1091.
"The Wizard of Wurtz," 25 Oct 1924, Union Jack Library #1098.
"The Amazing Affair of the Renegade Prince," Feb 1925, The Sexton Blake Library (First Series) #370.
"Absolute Authority," 28 Feb 1925, Union Jack Library #1116.
"A Problem of Proof," 23 May 1925, Union Jack Library #1128.
"The Strange Affair of the Mantel Register Grate," 8 Aug 1925, Union Jack Library #1139.
"The Mystery of the Swanley Viaduct," Oct 1925, The Sexton Blake Library (Second Series) #13.
"The Affair of the Crumpled Paper," 2 Jan 1926, Union Jack Library #1160.
"Threads of Fate," 16 Jan 1926, Union Jack Library #1162.
"The Plant of Prey," 21 Mar 1926, Union Jack Library #1171.
"Zentih Declares War," 10 Apr 1926, Union Jack Library #1174.
"The Mystery of the Masked Rider," 8 May 1926, Union Jack Library #1178.
"A Mystery in Motley," 5 Jun 1926, Union Jack Library #1182.
"The Mystery of the Mechanical Man," 17 July 1926, Union Jack Library #1188.
"The Affair of the Were Wolf," 29 Jan 1927, Union Jack Library #1216.
"The Trail of the Nameless Three," 7 May 1927, Union Jack Library #1229.
"The Case of the Friend of May Cubitt," 23 Jul 1927, Union Jack Library #1240.
"The Case of the Grey Envelope," 31 Mar 1928, Union Jack Library #1276.
"The Mystery of the Shot P.C.," Jun 1928, The Sexton Blake Library (Second Series) #155.
"The Affair of the Great Seal," 8 Sep 1928, Union Jack Library #1299.
"The Problem of the Broken Stick," 24 Nov 1928, Union Jack Library #1310.
"The Case of the Crook M.P.," Dec 1928, The Sexton Blake Library (Second Series) #173.
"The Humber Woodyard Mystery," 9 Mar 1929, Union Jack Library #1325.
"The Man Who Squealed," Apr 1929, The Sexton Blake Library (Second Series) #188.
"The Case of the Fifth Men," 15 Jun 1929, Union Jack Library #1339.
"Gangsters' Gold," 1 Feb 1930, Union Jack Library #1372.
"The Gangster's Revenge," Apr 1930, The Sexton Blake Library (Second Series) #233.
"The Crook's Accomplice," Jul 1930, The Sexton Blake Library (Second Series) #246.
"Killers' Creed," 30 Aug 1930, Union Jack Library #1402.
"Green Men," 8 Nov 1930, Union Jack Library #1412.
"Crooks' Fortune," 27 Dec 1930, Union Jack Library #1419.
"Night Birds," 3 Jan 1931, Union Jack Library #1420.
"The Vault of Doom," Apr 1931, The Sexton Blake Library (Second Series) #281.
"The Death of Four," June 1931, The Sexton Blake Library (Second Series) #291.
"Crook Crusaders," 9 Apr 1932, Union Jack Library #1486.
"The Fatal Mascot," Apr 1932, The Sexton Blake Library (Second Series) #331.
"The Rain Maker," 20 Aug 1932, Union Jack Library #1505.
"The Gold Maker," 24 Sep 1932, Union Jack Library #1510.
"The Derelict House," 5 Jan 1933, The Sexton Blake Library (Second Series) #368.
"The Box of Ho Sen," 15 Apr 1933, Detective Weekly #8.
"The Seven Dead Matches Mystery," 27 May 1933, Detective Weekly #14.
"Seeds of Sleep," 15 July 1933, Detective Weekly #21.
"The Crime Zone," 19 Aug 1933, Detective Weekly #26.
"The Case of the Shuttered Room," 24 Feb 1934, Detective Weekly #53.
"The Clue of the Corsican Collar," 30 Jul 1934, Detective Weekly #71.
"The Blinding Clue," 20 Oct 1934, Detective Weekly #87.
"The White Trinity," 18 Jan 1936, Detective Weekly #152.
"The Secret of the Six Locks," 25 April 1936, Detective Weekly #166.
"The Clue in the Blue Sampler," 11 July 1936, Detective Weekly #177.
"The Mystery of the Swanley Viaduct," 1 July 1937, The Sexton Blake Library (Second Series) #582. (Reprint of The Sexton Blake Library (Second Series) #13.)
"The Case of the Crook Oil-King," 2 Apr 1938, Detective Weekly #267.
"Zenith the Albino!," 29 Apr 1939, Detective Weekly #323.
"The Mystery of the Shot P.C.," Jan 1940, The Sexton Blake Library (Second Series) #703. (Reprint of The Sexton Blake Library (Second Series) #155.)
"The Case of the Grey Envelope," 6 April 1940, Detective Weekly #372. (Reprint of Union Jack Library #1276.)
"The Affair of the Bronze Basilisk," Apr 1941, The Sexton Blake Library (Third Series) #49.