There are four types of lizards in Tears of the Kingdom, and each one gives a different effect when cooked into elixirs. One of the lesser common but arguably more useful lizards are the 
Fireproof Lizards. As their name indicates, Fireproof Lizards will give Link flame-resistance, which is necessary when exploring areas surrounded by lava.
Fireproof Lizards prefer warmer, mountainous regions in Tears of the Kingdom. They even prefer caves with hot temperatures. As such, Players will have better luck farming Fireproof Lizards if they search the Eldin Region.
Fireproof Lizard Locations
Fireproof Lizards can be found along the path of the Goronbi River and inside most of the caves in the Eldin Region. However, players can also buy them from Beedle and Nembis, a Traveling Merchant near Kakariko Village.
If players haven't done so already, they should get the Sensor+ and the Hyrule Compendium from Robbie.
An easy way to farm Fireproof Lizards is to take Sneaky Elixirs or wear stealth-enhancing armor to lower the chances of scaring off the lizards. Fireproof Lizards can also be shot with arrows. Avoid using bows that use more than one arrow, as hitting them with 2x arrows will cause the Fireproof Lizard to disappear instead.
Goronbi River
Players can find Fireproof Lizards on the Goronbi River (1665, 1623, 0280) between Bedrock Bistro and Goron City. Since this is on The Surface, Link won't need to equip flame-resistant armor. Instead, players should wear armor that enhances stealth such as the Dark Armor Set from the Lomei Labryinths, or the Stealth Armor Set from Kakariko Village.
Buy Fireproof Lizards from Traveling Merchants
Players can buy Fireproof Lizards for 25 Rupees from two merchants in Hyrule: Nembis and Beedle.
Nembis travels with his horse, pulling a wagon of merchandise along the trail from Wetland Stable to Kakariko Village at 1142, -0619, 0013. Players can find him by taking the west road out of Kakariko Village. He's also the merchant to buy from if players are working on the "Gloom-Borne Illness" side quest. Nembis only stocks 3 Fireproof Lizards.
Beedle can be found at every stable (except the Gerudo Canyon Stable), but he only stocks Fireproof Lizards at the stables near Eldin:
- Woodland Stable (1057, 1122, 0022)
- South Akkala Stable (3125, 1687, 0201)
Where to Use Fireproof Lizards
Fireproof Lizards can be used to make Fireproof Elixirs when cooked with a Monster Part. However, a more worthwhile investment would be using Fireproof Lizards to upgrade the Flamebreaker Set to level 2. Players will need x5 Fireproof Lizards for each Flamebreaker Armor. They'll also need x5 Moblin Fangs.
Upgrading the Flamebreaker Set with the Fireproof Lizards is recommended thanks to the Flameproof Set Bonus (unlocked at level 2). This will prevent Link from being set on fire by enemies or while riding Dinraal's back.
The Legend of Zelda: Tears of the Kingdom is available for Nintendo Switch.