A while back I was looking for a list of journals that published letters-to-the-editor, essays, opinion pieces. I couldn't find a comprehensive list so I thought I would start one. I'll update it once in a while, let me know if you know other places.
Facets (Canadian open-access journal; publication fee waived until June 30, 2017)
Editorial: <1400 words, no author limit, references and figures OK
Note: Reports completed project of smaller scope
Perspective: Fully referenced thought-piece discussing scientific concepts and proposing new ideas
Science Applications Forum: Link scientific knowledge to policy, management, public interests, industry applications