The Keshavanand Bharati case (1973) is famously called the 'Fundamental Rights case' because it dealt with the scope of Parliament's power to amend fundamental rights under Article 368 and established the Basic Structure doctrine. While M.C. Mehta (environment), S.P. Gupta (judicial independence), and Champakam Dorairajan (reservation) are important cases, they don't hold this specific title.