Window Making Templates Source

[Grimmnar]

In the past i have seen templates done by different peeps a template to do different windows in shape, design and what not.
Think they have all been for 28mm give or take.
Seen them in acrylic and MDF. But sure nowadays someone is 3D printing them.
I got an acrylic one from Geronimo some years back.
Seen a chap on Facebook that had a nice 2 piece form that he did up himself.
Just looking to see what sources are out there.
So, who has got what?

Grimm