Popular black-box optimization techniques are implemented in the bbotk package. The corresponding connectors to for tuning hyperparameters of learners or pipelines reside as Tuner objects in package mlr3tuning. Additionally, packages mlr3hyperband and mlr3mbo provide some modern and sophisticated approaches.
All tuners operator on box-constrained tuning spaces which have to be defined by the user. Some popular spaces from literature are readily available as tuning spaces.