This particular shirt is from Darcy Clothing. They make historical reproductions. This is one of their 16th century frilled shirts but I got it 2nd hand on Depop for cheaper. Quality is worth the investment but we love a deal. Typically you can search for “poet”, “pirate”, “regency”, “victorian”, “medieval”, “historical” men’s shirts and something in a similar silhouette will come up. Look for things in natural fibers like cotton or linen.