The Wallace Correspondence Project (WCP) has not only catalogued Wallace's letters (available online in EPSILON), but also all of his other manuscripts, artwork etc, plus important documents written by family members. There are a total of 476 of these 'non-letter' manuscripts, and they include a number of Wallace's historically important notebooks, images of which are available online via the links below.
Artwork from the Amazon (1848 - 1852)
WCP5802: Wallace, Alfred Russel, Palms of the Amazon (c.1848 - c.1852)
A notebook on the palms of the Amazon, which also served as the manuscript to ARW's publication, Palm trees of the Amazon and their uses (1853). See http://linnean-online.org/54024/#/0
Malay Archipelago Notebooks
Field notebook with lists of birds and beetles collected in Singapore & Malacca in 1854. Repository: Linnean Society. CLICK HERE