Publishing open access journals has seen an explosion in popularity in recent years. Many resources provide access to their open access journals or provide a curated list of open access journals.
Athabasca University
Athabasca University is considered to be one of the leading institutions in the field of open educational resources. After the creation of the UNESCO/Commonwealth of Learning (COL), Athabasca was named chair of OER. Through the Commonwealth, they created the OER Knowledge Cloud which is a searchable database of OER resources such as articles, reports, and books.
UNESCO, Knowledge Cloud License: 
Athabasca License: 
PLOS
Plos is a nonprofit open access publishing organization that advocates the cause of open publishing. Their website provides a user with complete access to seven unique journals on subjects such as biology, medicine, and genetics.
License: 
DOAJ: Directory of Open Access Journals
The Directory of Open Access Journals is a database of scholarly journals which are open access. The DOAJ is supported by many of the major journal publishers and contains journals from the humanities, social sciences, and STEM subjects.
License: 
Digital Commons Network
Digital Commons Network is a website which provides full-text access to many articles. The articles are on a wide range of subjects including law, arts and humanities, and engineering. The articles are presented on the web page in a multicolored circle, with the innermost portion of the circle being top-level categories and the outermost portion being more specialized categories. Each colour in the circle represents a specific subject or discipline. The website also provides the option to search for specific articles.
License: No license listed
Knowledge Unlatched
Knowledge Unlatched is a site which will provide access to journals. The site, as of May 2017, is collection articles which will be open access and available to all users. The site provides a downloadable pdf which outlines their commitment to open publishing of journals.
License: No specific license listed