There is a blog that tracks the Tables of Contents of online, open access art history journals. The author of the site state that:

The aim of this blog is to collect the TOCs of new issues of open access journals in the field of art history. “Art history” is conceived here in a rather narrow sense. Although the header contains tabs like “Contemporary Art & Theory” or “Architecture” too, a comprehensive outlook on these fields is not intended. Periodicals of related disciplines are evaluated only if they have some art historical material too, this may however change in the future.

You can visit the site here and subscribe to its feed, you can also follow it on twitter.