The American Frugal Housewife (1832). Just a cookbook, but a relatively good-looking one from a period I don't have many of. And it has two different recipes for Indian Pudding, which I really must try making sometime.
Knots, Splices and Rope Work. Super-useful: a richly-illustrated guide to zillions of different ways to tie things. Be warned: takes a while to load, because there's a fairly big picture for almost every paragraph.
Library of the World's Best Literature, Ancient and Modern, v.5. Less period stuff here than in some, but has bits by Boccaccio, Boetius, St. Bonaventura, Juan Boscan (a 16th c. Spanish poet), and Sebastian Brandt (with a version of the Ship of Fools). Also v. 6, including The Abbe de Brantome, William Browne (an Elizabethan poet), and Giordano Bruno (a Renaissance Italian poet and mystic).
Ticket No. "9672", by Jules Verne. No idea whether it's SFish at all, but I figure there are some Verne fans out there.
The Excavations of the Roman Baths at Bath, for the students of Rome.
The Principal Navigations, Voyages, Traffiques, and Discoveries of The English Nation, Vol. XII., America, Part I. This is mainly a collection of primary source material relating to the very early history of America, in both original language (often Latin) and translation. Seems to be pretty much entirely period documents, running through the 1580s.
The World's Greatest Books, v. XIII: Religion and Philosophy. Excerpts from pretty much every major religious work, from the Egyptian Book of the Dead on up, plus a small smattering of philosophical bits. Mostly period.
Holished's Chronicles: The Historie of England, v. 2, picking up a generation or two after the fall of Troy, and running through Gorboduc. This is the old, legendary history, as it was understood in period -- neat stuff.
A Book of Nonsense, by Edward Lear. Probably the most famous collection of limericks ever written. Also his Nonsense Songs, More Nonsense, Laughable Lyrics, and Nonsense Books (which is mostly a collection of the above, plus a newly-added index).
Chapters on Jewish Literature. This is a book mainly about Jewish literature, although with many excerpts interspersed in it. The focus is mainly on the Middle Ages, although it runs a bit past SCA period.
A Trip to Venus (1897). Early science fiction, obviously. Fancies itself relatively hard SF. Expands upon Verne by advocating a "compound gun" -- a sort of multi-stage-rocket version of Verne's projectile spaceship.
Apology, Crito and Phaedo of Plato -- among the great classics of philosophy.
Characters from 17th Century Histories and Chronicles. A bit post-period, but close enough to be interesting. A smorgasboard of essays about 17th century figures by 17th century writers.
The Influence of Old Norse Literature on English Literature (1901).