PacletFind
PacletFind["name"] gives a list of installed paclets that match "name".
PacletFind["name"->"version"] gives a list of installed paclets that match "name" and "version".
PacletFind["name",<|prop1->val1,prop2->val2,…|>] gives a list of installed paclets that match "name" and criteria given by the propi->vali.
Please visit the official Wolfram Language Reference for more details and examples on core symbols.