Meetings software, channel-based chat, cloud storage, planning tools, there is probably untapped potential in the software packages you already have. if not, many vendors are offering free access to their apps for up to 3-6 months during the pandemic.
You can get a free 6-month Microsoft Office 365 E1 license (which includes Teams, SharePoint, OneDrive, Exchange & more. Elsewhere, Zoom has removed its 40-minute call limit in some countries, Citrix WebEx and Google Hangouts are giving away their meetings products for free, and a list of many more COVID-19 free offers is on Xlconsulting’s website here.
As well as Teams, Google Hangout meets, Zoom and Citrix WebEx Meetings are popular products. Personally, I find Zoom has the most advanced incall features, but Teams has the best ancillary features (pre/post call & the side chat). All products are free during COVID 19 (see intro paragraph for links).
Whilst collaborative conference calling for 2-250 fits the needs of most, the abovementioned companies also have a Live event/Webinar product, this is for broadcasting pre-prepared content from one/few to up to 10,000 viewers, managing a Q&A whilst the participants can’t show their own video or share their screen. Teams provides this in their standard package, but the other products require a costly additional payment. Microsoft is also offering free help to set up Teams live events, that I took advantage of recently.