Personally I don't know of any best practice. Several things come to mind.
A site is built around a purpose or theme i.e. HR, Sales, Marketing, IT
What's the purpose of the forms? Do they all fit under one category or theme i.e. HR.
I think it's best to think in terms of growth. Once you get one form, others are normally wanted.
As an example
Site is HR (theme)
Each form has its own form library i.e. Holiday, Leave of Absence, TOIL, Staff Overtime
Each workflow is attached to a required library.
If you make your forms/library consistence if look and feel, users pick it all up very quickly.
This way if you want a change to 1 you're not affecting others by accident. All this allows you to learn and progress your own skills and development.
Remember this: what you design and how initially is invariable not how people use It!