Software
For my simulations I use the free, open-source Einstein Toolkit code, which is based on the Cactus infrastructure. During my PhD, I built a module called FLRWSolver to feed cosmological initial data into the Einstein Toolkit. A brief tutorial on running a simple simulation (after following download and compile instructions on the Einstein Toolkit website) can be found here. FLRWSolver is included as a part of the Einstein Toolkit as of the twenty-fifth ``Sophie Kowalevski'' release onwards. To extract interesting things from Cactus in post-processing we use the analysis code mescaline which is available here.
Data
A set of simulation data from my PhD is freely available for download here. I am happy to share newer simulation data (which is easier to use) on reasonable request. Please don't hesitate to contact me about getting access to this. Some synthetic observations from a paper of mine investigating the Hubble tension is publicly available here.