This list is very much a work in progress, and in its earlier stages. Some things I'd like to add more of: kehilot, nusah, and siddurim from outside the US; teachings from Sephardic women.
Note: This list uses the term Sephardic in the pan-Sephardic sense of the word (ie inclusive of Mizrahim, as well as including traditions that weren't necessarily based in Sephardic Rite - i.e. Kavkazi, Gorski, Yemenite, Romaniote, Italki, etc). [I’ll expand a bit more on this later]
Cookbooks: In English, I can't recommend Claudia Roden's "The Book of Jewish Food" enough - she centers Sephardic cooking rather than Ashkenazi cooking, and goes into incredible detail on Sephardic and Mizrahi culinary practices. I also recommend dafina.net (in French) for Moroccan Jewish food and a cool forum, and the work of Janet Amateau, who has written several books and has a good blog at Sephardic Food.com. Le Culte de la table dressee in French, by Joelle Bahloul, is an incredible resource for Algerian Jewish cooking.
Other resources: Gil Marks' Encyclopedia of Jewish Food is really good for ingredients and cooking methods, and details a lot on Sephardic influence on Ashkenazi food going back to the 1300s. Eat and Be Satisfied by John Cooper is also great. The Taste of Conquest by Michael Krondl is really good for the history of the Spice Trade, and also check out stuff on the Dutch Jewish Atlantic and Sephardic Dutch Jews by Jessica Roitman. For broader influences on Sephardic Jewish cooking, Rachel Laudan's Cuisine and Empire is one of the best books on food I have ever read. I need to find the citations on the herring industry, fish and chips, and the jam industry tomorrow - all of which were developed by Sephardim in Northern Europe.