Despite the fact that I am tired of reading paper's on natural experiments, there is one contribution in this field that captured my attention. Not only the topic is fascinating (Switzerland offered up to two years of income tax exemptions to its inhabitants), but also because the results are quite surprising: almost no behavioral change occurred. Here is the reference:
Martínez, Isabel Z., Emmanuel Saez, and Michael Siegenthaler. 2021. "Intertemporal Labor Supply Substitution? Evidence from the Swiss Income Tax Holidays." American Economic Review, 111, 506-46.
In a fully different style, I appreciate Laurent Linnemer's paper on Jean-Jacques Laffont very much. I have read several papers by Jean-Jacques Laffont, but knew not much about him.
Linnemer, Laurent (2021). Le Magnifique Jean-Jacques Laffont (13 April 1947 - 1 May 2004). Annals of Economics and Statistics, 143, 1–69.