Some journal indexes order journals according to their 'quality', while other indexes function more as a directory.
There are both national and international journal indexes, as well as indexes for specific academic fields, which order journals according to their 'quality'. Journal Impact Factors are frequently mentioned, however in some academic traditions, journal rankings are more widespread.
In the context of Danish research, it makes sense to look at the Danish Bibliometric Research Indicator (BFI), which distributes research funding among Danish universities on the basis of the number of publications. The BFI is an incentive model that supports collaboration and publication in prestigious journals and by prestigious publishers.
One journal index that functions as a global directory of journals is Ulrichsweb, which enables you to compare specific journal characteristics, such as peer-review or database indexing.