The publishers of large format visual arts books such as exhibition catalogues do not supply ebooks to libraries, so are unlikely to be able to join in with these initiatives. This includes even relatively large publishers in that area such as Phaidon, Taschen and Thames & Hudson.
Individual publishers might have relevant initiatives.
Individual artists/writers may have material on their own websites. For example:
Some museums have made selected catalogues available. For example:
The Internet Archive and related Open Library can be good for older material for arts subjects. Some examples include:
Google Books has extensive previews of some texts submitted by publishers to promote their content, including recent texts. For example:
Project Gutenberg is strictly limited to out of copyright books. Examples include:
There are a few interesting commercial initiatives currently available. For example:
Open Access monographs published by University Presses are often searchable in the DOAB directory and in JSTOR Open. It may also be worth browsing the individual catalogues of the presses. A few suggestions are listed below.