blmpop

BLMPOP is the blocking variant of LMPOP.

When any of the lists contains elements, this command behaves exactly like LMPOP. When used inside a MULTI/EXEC block, this command behaves exactly like LMPOP. When all lists are empty, Valkey will block the connection until another client pushes to it or until the timeout (a double value specifying the maximum number of seconds to block) elapses. A timeout of zero can be used to block indefinitely.

See LMPOP for more information.