The marginaleffects package for R 
marginaleffects allows users to compute and plot predictions, slopes, marginal means, and comparisons (contrasts, risk ratios, odds, etc.) for over 80 classes of statistical models. It can conduct linear and non-linear hypothesis tests, or equivalence tests, and calculate uncertainty estimates using the delta method, bootstrapping, or simulation-based inference.
The marginaleffects
book (website) includes
a “Get
started”
page, and over 25 chapters full of tutorials, case studies, and technical notes.