Five of my favorite tools which has made remote work, work, over the years for me and those I collaborate with are:
Dropbox - Invaluable for any kind of fiel sharing and transfer. Particularly useful if you have large documents, video files and any other media that you need to send for review, reading and use. Dropbox has free accounts and you can also upgrade to a Business Account. I haven't come close to my 1T of data storage with my Business Account, and I have found it being used by organizations of all sizes today.
Skype - Lynx recently became Skype for Business, and Skype is really a global telecommunications tool. Whether you are able to go with video based calls, or voice only. Skype provides an excellent platform for 1-1 conversation as well as small group conversation. Group calls also allow for slide sharing. One caveat, with the different versions of Windows, the range of devices, and other platforms you may have access to the "full version" of skype or a "lighter" version which may not allow you to establish group calls, only join them.
Zoom is another great virtual meeting space and allows for both dial in and video streaming access. The nice thing about zoom is that it is very user friendly with respect to screen sharing and recording. Free accounts currently allow you to establish as many meetings as you would like for up to 40-45 minutes a time.
Google Docs is another invaluable resource for working on documents collaboratively. As with other platforms consider the security needs of the projects/documents you are working on.
And for those that work remote on a regular basis you may want to stake out some other working locations if your own location is not keeping you focused. on a monthly basis I head to a couple of different libraries for writing, research or even focused projects. I'm a very productive person generally and find that these locations give it a booster shot, perhaps because I limit my time there and always go with a project/task or two in mind. Finally co-working spaces offer the benefit of being around others, and having space to work.