nordicnames.de is not that bad actually. The authors of that site cite their sources (and often provide different sources with diverging explanations). One has to be careful when they either give as source "Own estimate" or give no source at all.
With some names I have also the problem that they may occur in (prescriptive?) name books, but I cannot find any evidence of use. The
Sami namedays are an example of this.
All in all: It does not make any sense to copy names and explanations from another website without own thought and judgement.