Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Citavi - Citavi is a program for Microsoft Windows that manages literary references and organizes organizational knowledge.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .
Slack - A messaging app for teams who see through the Earth!