The Getty Research Portal has links to a series of Edward Lear-related books; what I think is the first digital edition of
Views in Rome and Its Environs. London: Thomas McLean, 1841.
as well as
Illustrations of the Family of the Psittacidae, or Parrots. London: R. Ackermann & E. Lear, 1832.
Gleanings from the Menagerie and Aviary at Knowsley Hall. Edited by E. Gray. Privately printed, 1846.
Eyton, Thomas Campbell. A Monograph of the Anatidae, or Duck Tribe. London, 1838. (first online)
And a few others. Links to the new resources have been added in the relavant bibliography pages.