Unfortunately, the digital age hasn’t led to many reprints of exact copies of vintage illustration plates (though many of the classic illustrations of Audubon and the like are used as solitary figures), but there are some available on Amazon, if you want a collection of the plates. Your best bet is to search by author (e.g. Audubon, Haeckel, etc). There are also a few that deal with specific time periods of scientific illustration, such as Nature Illuminated.
Personally, the best one I know of is Amazing Rare Things: The Art of Natural History in the Age of Discovery, by David Attinborough et al, though it contains a good deal more writing about the art of scientific illustration than it does artwork itself (though it does contain a fair amount of that, too).