makehuman is an open source tool that I use to create custom faces http://www.makehumancommunity.org/co...downloads.html
houdini is the industry standard tool for visual effects. It's node based which is super useful but it can take a little while to get used to. They have a free apprentice version https://www.sidefx.com/products/houdini-apprentice/
Like a lot of 3D tools the interface is a bit too busy so if you want to dig around I recommend using the creation ui http://houdinicreationdesk.ipage.com/index.html
Also I like to use headus for uv mapping https://www.uvlayout.com/try/
I use xnormal to make my normal maps https://xnormal.net/
If you'd like any tips on using these tools let me know.