Which non depolarizing agent is a ganglion blocker –
Non-depolarizing muscle relaxants causing ganglion blockade → d - tubocurarine (maximum propensity), metocurine, Alcuronium.

Remember

Maximum ganglion blockade and maximum histamine release is caused by → dTC.
Maxim um vagal block (max. vagolytic action) is caused by → Pancuronium (Previously it was gallamine, but it is not used now).
Atracurium
Pancuronium
D–TC
Gallamine