For your convenience: good gold leaf supplies (and other metal leaf) from reliable US-based suppliers.
(UK- and Europe-based gold leaf supplies here.)
Everything below is from vendors I can vouch for. Amazon is an old friend now who gives me small commission on sales through this site. The others are well known and trusted either from direct experience or because close artist friends have used and recommended them.
Note: always read reviews/answered questions where available. Also note: links below open a new window each time so you can compare products side by side. If you don’t want that, just start new searches in the first window that opens for a site.
Good quality products, sound packaging, speedy delivery and efficient customer service. Yay! That said, the gold leaf supplies are fulfilled by third-party sellers: check before ordering whether products qualify for free shipping.
Price comparison is the thing, and since new products and sellers arrive all the time, it makes sense to give search result pages not specific products ... do sift through for the best deal. (I worded the searches as carefully as possible but you know how it is: some irrelevant product always creeps into the main list ... and check the ‘also-ran’ products at the bottom of the page for overlooked bargains.)
Edible gold leaf falls between 23 and 24 karat – perfectly good for calligraphy, and doubles as deco for your hand-dipped truffles.
Suppliers of a variety of metal leaf including aluminum, copper, and real silver. NB they also stock two sizes of shell gold. Natural Pigments is a wonderful place for old-fashioned pigments.
Kremer's gold leaf and shell gold range is very good. Not cheap but excellent quality.
Kremer also do real silver leaf both loose and transfer.
Let me know how you go.