Silver Llamas in Fortnite
Silver Llamas can be found by bashing open the standard Upgrade Llamas in Fortnite. Purchasing an upgrade Llama costs 100 V-Bucks. Upgrade Llamas are the main type of Llama, and they can be seen on the image below.
After hitting an upgrade Llama in Fortnite, it has the chance of turning Silver (as seen below). Silver Llamas will offer a larger amount of rewards, and items that are much higher quality. This includes Heroes, schematics, survivors and more.
After receiving a Silver Llama, that then has the chance of turning into a Golden Llama. In a golden Llama, you can expect a guaranteed legendary item. A golden Llama is the highest tier of the Upgrade Llama, and offers the best rewards by far.
Above is some of the loot received from opening a Silver Llama in Fortnite.