I recently made software code for implementing Mendelian randomization analyses available as a GitHub-editable document. The motivation for this is that much of this code is scattered in the appendices of various manuscripts, and is hard to find, hard to edit (when you want to update), and the notation isn't always consistent.
Code can be found here, and the associated project is here. Please read through and get in touch if you spot any typos, or else edit yourself! The document currently contains mostly R code with some Stata code, but other software code would be welcome. This is a new initiative: feedback is very welcome.