Here are some Open Source tools that can help with remote work:

- @Matrix.org (and Riot.im or any other compatible client): chat, instant messaging (full disclosure: I work on Matrix.org as my full-time job)
- @CryptPad: collaborative real-time document editing, kanban boards, spread sheets, and more
- meet.jit.si: video conferencing
- www.loomio.org: discussion and decision making