A good many of those embroidered vignettes were purchased and what's more---they were machine-embroidered. Kursheedt's in New York was one of the big commercial sources for the pictorials. They held the patents on the embroidery machines.
"If ladies have no time to embroider...they will find the Kursheedt's embroidered color silk appliques most convenient."
"Crowley's Fibre Letter Foundations,"Crowley's Department Stores in Chicago and Detroit, 1920-1950. I made a few completed samples to display, as I'm selling the individual monograms in my antique shop. I basted the forms onto my background fabric and then hand stitched a satin stitch using pearl cotton. After experimenting with the 1st one, they became easier to do and each looked better than the last."
These are forms or templates that one could embroider over while attaching them to a background.
But---like the hummingbird above: Could you buy finished initials either as slips to attach to a background or as finished machine embroidery on a fabric background to cut to fit in your crazy quilt?
I searched in newspapers, magazines and online auctions for words like: "monogram---initial---crazy quilt" and found two copies of this catalog The Initial House from G. Reis and Bro. who would sell you embroidered monogram initials, which is probably what we have been seeing on crazy quilts for years, believing the quiltmaker stitched them.
Once you know the words to search for you find a lot of evidence for the existence of machine-sewn letters and numerals. In 1910 Reis gave us names for the product: "Padding Letters, Skeleton Letters, Embroidery Forms, Foundation Letters and Embroidery Foundations."
Terms like Skeleton Letters and Embroidery Forms make one wonder if they are also talking about templates, machine-cut letters that you attached to your background and then satin-stitched over the skeleton.
Carol Leather found some British letter forms and tried it. Quite a nice look.
#1 take your material to a printer or artist to be stamped.
#2 buy material that already has been stamped , embroider it then applique.
#3 buy pre made appliqué and sew it on.
#4 buy a hot iron transfer to stamp your fabric with.
#5 buy a stencil (perforated patterns are a type of stencil) and stamp your own.
Why don't we use "Skeleton letters" to make slick embroidered labels?