The Pickaxe is a melee weapon you can unlock through the Beavis and Butthead event. It's unlocked towards the end of the event pass on the free track. If you play Black Ops 6 after this event ends, ...

The Olympia is a secondary weapon that's unlocked through the Beavis & Butthead event. If you're playing Black Ops 6 after this event ends, you may unlock the Olympia through Armory Unlocks instead.