1. There is a brilliant open access database on materials called MATERALS PROJECT which is maintained by Lawrence Berkeley National Laboratory. You can find thousands of materials and their properties in there. They also provide a material analysis code called PYMATGEN which can be used to built material systems. You need some python knowledge to use it. But, you can learn it from their workshops on YouTube channel and from the Github page. Links are below,
https://materialsproject.org/
https://www.youtube.com/@MaterialsProject
https://github.com/materialsproject/pymatgen
2. The second option is building your own structure with VESTA. VESTA is also an open source visualization and structure building software. There are many tutorials for the VESTA software in YouTube. Please see the following links,