txpool_content
The content inspection property can be queried to list the exact details of all the transactions currently pending for inclusion in the next block(s), as well as the ones that are being scheduled for future execution only.
The result is an object with two fields pending and queued. Each of these fields is associative arrays, in which each entry maps an origin-address to a batch of scheduled transactions. These batches themselves are maps associating nonces with actual transactions.
JSONRPC: txpool_content