The foundation gieffektivt.no allows Norwegian taxpayers to get tax deductibility for donations to effective charities within global health and development (all of GiveWell's top charities).
If you pay taxes in Norway, then donations up to 50 000 NOK per year through gieffektivt.no are tax-deductible. This might allow you to reduce your taxes by up to 11 000 NOK per year, which could enable you to be more generous and donate more than you initially thought.