The Meertens Institute database of given names in the Netherlands reports a total of 1687 people with the spelling IJsbrand and 321 with the spelling Ysbrand as first or middle name, with other spellings occurring with 25 or fewer counts.
The Meertens Institute's database of Dutch names shows a total of 1687 individuals named IJsbrand or Ysbrand as first or middle name, alongside other less common variations that occur in under 25 occurrences.