Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Overleaf - The online platform for scientific writing. Overleaf is free: start writing now with one click. No sign-up required. Great on your iPad.
Qiqqa - Qiqqa is a free research and reference management software. It can be used in many organizational projects from the academic to the personal to the business endeavor. Read more about Qiqqa.
TeXstudio - TeXstudio is an integrated environment for writing LaTeX documents.
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .
LyX - LyX is a document processor.