R package metaheur. Automation of preprocessing often requires computationally costly preprocessing combinations. This package helps to find near-best combinations faster. Metaheuristics supported are taboo search, simulated annealing, reheating and late acceptance. Start conditions include random and grid starts. End conditions include all iteration rounds completed, objective threshold reached and convergence. Metaheuristics, start and end conditions can be hybridized and hyperparameters optimized. Parallel computations are supported. The package is intended to be used with package ’preprocomb’ and takes its ’GridClass’ object as input.