As the interest in macroeconomics atracted more economists, many became unsatisfied with explanation of economic events and remedial policy prescribed by the established macroeconomic theory...
Challengers of Keynesian:
New Classical Economics
Real Business Cycle Theory (strong root in Classical)
New Keynesian Theory (strong root in Keynesian)
Check how each group proposed their own explanations on economic events from 1970s to the 1990s, abd remedial prescriptions.