If you answered "Yes" to any of the questions above, this repo is for YOU!
Changing colors in Power BI themes is fairly straightforward. For formatting, the wildcard() to make universal changes is convenient. If you want to go deeper into individual visual properties, however, it can quickly get confusing. With these sample templates, explore the individual properties available to each* visual (as well as shapes and images). Combine the per-visual templates as needed, alter the values to correspond to your own needs, and build your own Power BI theme.
The purpose of this repository is to provide detail-level reference for each native visual in its own separate file. Look at the format options for a visual in Power BI Desktop and compare to the JSON options side by side. Copy and paste what you need from each visual's JSON to assemble a master Theme file.
Please note that the values in these sample files will appear ugly. Many values are not Power BI's defaults. As soon as something worked, I moved on to the next property. Please modify or remove properties in your own theme file to be what you desire.
Adjust titles, backgrounds, report page tooltips, wallpaper, and more for some or all visuals on a page or all pages.