While I may maintain some samples here, the SharePoint team has set up a repo of their own for Column Formatting examples and documentation. I recommend you use their repo instead of this one, as more people can potentially benefit.
This is a repository for "recipes" to use SharePoint Column Formatting for fields in list views. Each recipe here should be considered an example, not necessarily a final solution. The goal is to add enough recipes to this cookbook to help people get started building their own solutions - generally by tweaking a recipe a bit.
If you have a Column Formatting example you'd like to share, please do a Pull Request. If you aren't sure how to do that, you can also email your example to firstname.lastname@example.org.
Conditional formatting based on a number range (basic)
Taken from the Column Formatting sample page, this recipe formats a number where the value is below a specified number by adding an existing CSS class. number-formatting.json