flowr: A R package to streamline design and deployment of complex scientific workflows. It is available from the R repository, with detailed description available at docs.flowr.space.
params: A package to simplify the use of parameters, available on CRAN and summarized here.
funr: A small utility which wraps Rscript and provides easy access to all R functions from the terminal, available on CRAN and summarized here.
A few others, in alpha stage