90 top U.S. think-tanks starting with C, and 48 other ones :
councilonstrategicrisks.org
climatepolicylab.org
counterextremism.com
cisa.ndu.edu
cesionline.org
digitalcommons.ndu.edu
chinapower.csis.org
ccap.org
climatepromise.undp.org
cleanpower.org
cartercenter.org
clasp.ngo
ceaconsulting.com
cof.org
40knowledgehub.org
ciwaprogram.org
csce.gov
cjoscoe.org
civicpulse.org
centralasiaprogram.org
cacianalyst.org
castellum.ai
criticalthreats.org
carbonbusinesscouncil.org
climateknowledgeportal.worldbank.org
caspianpolicy.org
campaignforaccountability.org
ciphernews.com
civiliansinconflict.org
cpj.org
cryptoforinnovation.org
chainalysis.com
ccsi.columbia.edu
capitalresearch.org
cybersolarium.org
criticalissues.umd.edu
cyberlaw.stanford.edu
climatefundsupdate.org
climatecasechart.com
climateattribution.org
carbon180.org
unu.edu/cpr
cltc.berkeley.edu
cimsec.org
coruscant.therussiaprogram.org
ciel.org
cisac.fsi.stanford.edu
disasterphilanthropy.org