i didn't saw any dedicated category for FreeCAD software. it is a good free alternative with many capability.
it is completely free and you can download it here: https://www.freecadweb.org/downloads.php
one of its usefull possibility is to visualise and convert all well known files formats
for those interested , below some short basis tutorial
https://www.youtube.com/watch?v=IN0tHR0MKCE
https://www.youtube.com/watch?v=zrSBAsQg8PM
https://www.youtube.com/watch?v=Vs5pq1jfNa4
https://www.youtube.com/watch?v=BgVsRU1nBJo
https://www.youtube.com/watch?v=04MLFzzxq-0
https://www.youtube.com/watch?v=lt__asVyRVs
https://www.youtube.com/watch?v=fL6t_lOnyQ0
https://www.youtube.com/watch?v=L_tuvnViWck