Well, considering Godot 3.1 is not even out yet, it is unlikely you'll find a set of export templates.
However, you can use daily builds and get the exported templates there (generally only for desktop platforms). Then for each export preset you just need to set the "custom template" fields to point to the daily build templates for the desired platforms.
You can find up to date daily builds from godot.hugo.pro, for example. On godot.hugo.pro you can find export templates for Windows, Linux, Android, and IOS.
