Log Collections are Bearer's way of creating filtered "buckets" for logs. Each log collection allows you to define a set of filter rules that can apply to some or all APIs. When a log matches the filter set, the log will be captured by the log collection.
Log Collections are a great way to find specific log entries, without the need to sort through all of the API calls your application makes. We think it's the best way to "find the needle in the haystack" when debugging.