Lost Marbles are something you can find in the different zones you’ll visit during your adventure through Tiny Tina’s Wonderland. Here you’ll be navigated to the Lost Marbles which are scattered around Ossu-Gol Necropolis.
Lost Marble Location #1 - The Cairn-City
Progress through the Ossu-Gol Necropolis until you reach The Cairn-City, then walk northeast and climb up into a small watchtower to find the first Lost Marble.
Lost Marble Location #2 - Sandchocked Catacombs
Make your way down to the Sandchocked Catacombs, then keep to the left side of the area where you slide down and you hop up onto a small stone to find the second Lost Marble.