Lost Marbles is something you can find in the different zones you’ll visit during your adventure through Tiny Tina’s Wonderlands. Here you’ll be navigated to the Lost Marbles which are scattered around Tangledrift.
Lost Marble Location #1
Go to the What’s Left of Driftwood fast travel station and head to the house to the northwest of it, along the cliff. On the edge of the cliff, if you peer over it to the north, you should see a blue portal. Jump down and hit the portal, which will send you to a ledge inside the broken tower to the west of the fast travel station. The Lost Marble will be right there, on that ledge.
Lost Marble Location #2
Go to the What’s Left of Driftwood fast travel station and locate the landmass to the east of it on your map. On the northern side of that landmass, there are some small islands you can jump down to, one of which will contain the Lost Marble. Be very careful when jumping to the island with the Marble, as a strong gust of wind will blow every few seconds right before it, which can knock you down into the abyss, causing you to die.