A "fields set" for repetitive insertions

I often need to insert the same set of fields in my tables. While I have only a single "fields set" to replicate, then I use a table template where I start from, but when I need to insert two different "fields sets" in the same table (not always the same) I have some problem. 
I'd like to be able to define objects like like "copybooks" or "includes" (containing fields definitions) to be picked up and then inserted in my tables. These "objects" could stay in a sot of "custom library"

Nice to have...