Historical clue formulations

• Undercover operatives — 2026-03-31
• Plants, maybe — 2025-04-18
• Masters of disguise — 2024-12-20
• Many John le Carré characters — 2024-08-30
• Secret traders — 2023-12-27
• People who might bug others — 2022-05-24
• John le Carré heroes — 2017-09-26
• Spooks — 2016-12-03
• Secret collectors — 2016-01-24
• 007 and others — 2015-08-10
• Some "Bourne" film characters — 2013-02-03
• They may work for both sides — 2011-09-16
• Fears of some paranoiacs — 2011-05-26
• Black and white Mad magazine figures — 2010-04-21
• Black-clad and white-clad Mad adversaries — 2009-04-21
• Uses a tap, perhaps — 2005-10-21
• Those seeking intelligence — 2000-04-09
• People who aren't what they seem — 1998-10-07
• Cloak-and-dagger types — 1995-04-17
• Spooks — 1995-04-15
• 1928 Fritz Lang thriller — 1995-02-26
• Sometimes they get the hang of it — 1994-01-17