Where to find drawings

I think you'll have the best success drawing the desired shape/pattern.
I'd do some image searches and see what types of shapes are out there which you find attractive.
Obviously search for fencing, but expand to privacy screens, decking panels, and any other sites which show 2D ornamental patterns.

Most of the images found online could be redrawn in a short period of time, but there are also programs (vector magic is one) which will help convert raster images to a vector format like DXF.

https://www.google.com/search?hl=en&biw=1270&bih=901&tbm=isch&sa=1&ei=4pTPW_6xKsKYjwTQ0JqIBw&q=privacy+screens&oq=privacy+screens&gs_l=img.3..0l10.83988.87239..87398...0.0..0.122.1300.13j2......1....1..gws-wiz-img.......35i39j0i67.llNRAML42uA

What type of drawing you need, is about “punch” or actual design of gate?

mam can you tell me the model ID of your CNC punching machine ?