The listwallets RPC returns a list of currently loaded wallets.
listwallets none
*bitcoin-cli help listwallets
listwallets Returns a list of currently loaded wallets. For full information on the wallet, use "getwalletinfo" Result: [ (json array) "str", (string) the wallet name ... ] Examples: > bitcoin-cli listwallets > curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "listwallets", "params": []}' -H 'content-type: text/plain;' http://127.0.0.1:8332/