grpreg: for fitting regularization paths of regression models with grouped covariates [CRAN]

ncvreg: for fitting MCP- or SCAD-penalized linear and logistic regression models [CRAN]

visreg: for visualizing the fit of regression models [CRAN]

If you encounter problems or bugs using any of these packages, please let me know -- good software depends on getting feedback from users. When doing so, please provide a minimal reproducible example.