Historical clue formulations

• "Richard of York gave battle in vain," for the colors of the rainbow — 2025-09-10
• Memory device like "How I wish I could calculate pi," e.g. — 2022-12-26
• "Thirty days hath September ...," e.g. — 2018-05-12
• Loss prevention association? — 2017-12-30
• "Every good boy does fine," e.g. — 2014-07-10