Edit: The problem in Teams has been solved by Microsoft since the question was asked: Teams screen sharing sessions now capture the mouse pointer also on Linux computers. This makes this question asking for a workaround obsolete. However, the solutions presented in the answers may still be applicable for other applications.
I'm doing screen sharing with Microsoft Teams on Linux. My mouse pointer is not visible to the people I share the screen with. This is a known shortcoming of the Linux version: https://docs.microsoft.com/answers/questions/3222/mouse-pointer-not-visible-when-sharing-screen.html
I'm searching for workarounds. Today I have used a terminal window, resized it to the smallest possible size and told people 'look at the upper left corner of this window' while dragging that terminal window across the screen to point out the parts of the screen that I want to draw attention to. I want to find a better workaround.
Use an image with transparency. An improvement over dragging around a terminal window would be to drag around an image of a mouse pointer with transparency around the mouse pointer. The tool 'display' from imagemagick had this property that when displaying e.g. a png image with transparent pixels, it would show the screen content behind those transparent pixels. The current version on ubuntu 18.04, however, shows an opaque checkerboard pattern instead. Is there another image display tool in Ubuntu that can still display transparency in an X11 window?
Have some application display a bright-colored circle (or something else) at the position of the mouse pointer on and off in intervals. Is there an application that can do this?
I am using Ubuntu 18.04, with the default desktop environment (the default desktop is called "ubuntu" on 18.04, it is based on gnome but preconfigured by canonical to resemble the discontinued "unity" desktop).