It would be great if there is a possibility to add Cryptomatte support on D5, Cryptomatte is a more robust system to create masks based on object names, material names or more custom rules (the most common used are the object and material names) and a lot of render engines offer this to facilitate the compositing process of the images.
Cryptomatte:
The current MaterialID Pass is not convenient for some cases because, on non-destructive workflows, the colors can change if the geometries of the scene can change. Also sometimes the selection created with this kind of pass sometimes needs a bit of work on the borders due to the filtering caused by the Magic Wand or the selection tool used.
Also sometimes the Material ID pass does unexpected sections from the same object or from the same Material, having to create multiple selections to be able to select only one material, as you can see on the example below:
In case that someone wants to see more information about it, here is the Cryptomatte section from Corona User Guide:
I hope that this result interesting for someone else too,
Thanks!