The campaign grouping feature is a powerful way to group and filter campaigns from multiple ad platforms. More on that here: How to build a campaign group?
The search filters are based on regular expressions. Below you can find a couple of use cases. And if you want more information or if want to experiment with or test regular expressions go to https://regex101.com/.
If you want to (automatically) select campaigns that have either "Winter" or "winter" in the campaign name, use the pipe | as a separator: "Winter|winter". You can use as many pipes as you like. This will help solve inconsistenties in the naming.
Select all campaigns
Use a dot (.) and press 'Apply filter'. This will bring all campaigns from the "Select" column, to the "Selected" column.