The Nostalgia set of Teams background images includes Office Clippy, the famous Bliss image used for the Windows XP desktop, and images of Paint and Solitaire. These are only part of the wide selection of suitable images to use as background effects in Teams meetings. And if you’ve got a great image to share, you can upload it to the Microsoft Gallery for others to use.
Microsoft has updated the Teams meeting policy to introduce a new control over video filters in Teams meetings. The VideoFiltersMode setting controls if people can use background blur and background effects, including the ability to upload custom images. A client update is needed to respect the new setting. It will come at the end of May.