Free and/or open-source software alternatives for churches

I've been seeing some cool software in the church space lately with lots of fancy bells and whistles that handle many different aspects of running a church (social, presentation, tithing, etc.). However, not all churches, especially small ones, can afford them or have members savvy enough to set it all up and maintain/operate them. I thought this could be a cool thread for free and or open source software that churches can use can use (Does not necessarily need to be design specifically for churches).

EDIT
Here is a list of paid examples:

• Renewed Vision
  • ProPresenter
  • ProVideoPlayer
  • ProVideoServer
  • Scoreboard
  • ProContent
• Microsoft Office
  • PowerPoint
  • Excel
• Google
  • Slides
  • Sheets
  • Forms

Here is a short list of FOSS alternatives:

• Free Show
• Owncast
• Rock RMS
• Choyr
• OBS
• OpenLP
• WorshipTools