Free Print samples

Catprint - Envelopes, paper, print samples
https://www.catprint.com/sample_requests/new

Uprint sample kits
https://www.uprinting.com/samples.html?

Printdirtcheap sample packs
https://www.printdirtcheap.com/free-sample-pack-cheap-printing/?

Moo Printing Large sample Pack
https://www.moo.com/us/sample-packs/all-products-sample-pack

Vistaprint
https://www.vistaprint.com/sample-kits/business-sample-kit?

Gotprint
https://www.gotprint.com/products/sample-kits/free-samples.html?

Epson print sample - Pictures
https://epson.com/large-format-printers-request-print-samples

Printing for less
https://www.printingforless.com/printing-samples-request/?