Historical clue formulations

• Archrivals — 2024-05-08
• Pokémon's Gary and Ash, e.g. — 2022-10-15
• You can't beat them — 2018-12-22
• Formidable opponents — 2018-03-09
• Fearsome foes — 2016-04-30
• They're unbeatable — 2013-12-12
• Formidable foes — 2013-05-03
• Formidable opponents — 2011-12-27
• Formidable opponents — 2010-03-29
• Batman and Robin, to Catwoman — 2002-10-12
• They're unconquerable — 2002-03-24
• Plan foilers, perhaps — 2001-07-06
• Banes — 2001-04-29
• Tough opponents — 2000-07-08
• Batman and Superman, to villains — 2000-02-13
• Agents of retribution — 1999-09-01
• Superheroes, to villains — 1999-07-31
• Formidable opponents — 1998-02-21
• Waterloos — 1998-01-11
• Archenemies, maybe — 1997-11-30
• They give comeuppances — 1995-05-20
• They can't be beat — 1995-01-12
• Thorns in one's side — 1994-10-21
• They can't be beat — 1994-06-10