You find Lynel Spears in The Legend of Zelda: Breath of the Wild by defeating Lynels, especially in areas like the Gerudo Highlands, West Necluda, and Deep Akkala, with different types (Mighty, Savage) dropping from stronger Lynels, though regular Lynel Spears from red-maned Lynels are scarce and may require specific conditions or scaling.
They are most commonly found in the Gerudo Highlands and West Necluda, though they can only be obtained by defeating Lynels. Being made of metal, Lynel Spears will attract Lightning if they are equipped during Thunderstorms and conduct Electricity.
Lynel Hooves are Monster Parts that can be found by defeating all types of Lynels. They're heavier than horse hooves and can be used in a Cooking Pot with critters to make Elixirs. The Kochi Dye Shop also accepts Lynel Hooves as an ingredient for Black Dye, but they can also be exchanged for Mon at the Fang and Bone.
Breath of the Wild
Mighty Lynel Spears have a base power of 20, and can be obtained by defeating Blue-Maned Lynels scattered in the overworld, for example in Deep Akkala.
In Botw, Lightningblight Ganon was the hardest boss. However, even that doesn't compare to the Lynels. In Totk, the most difficult I've faced so far is the Armored White-Maned Lynels in the Depths.
Lynels appear as Minibosses in Cadence of Hyrule. They have five Hearts and fight using their bow and arrows similar to Breath of the Wild.
Blue-Maned Lynels (HCN 148) are one step up from Red. White-Maned Lynels (HCN 149) are even more difficult to beat and fairly rare. Silver Lynels (HCN 150) are the most difficult to defeat and the rarest.
Finally, Walton asks Link to find an Item that starts with "h" and ends with "oof", and it is dangerous to have this step on you. This final answer is a Lynel Hoof, which is dropped by all types of Lynels when they are defeated. After solving all five riddles, Walton will give Link a Diamond as a reward.
Lynel Guts are Monster Parts that can be dropped by all types of Lynels upon their defeats. They pulse with the vitality of a Lynel, which makes them useful for making Elixirs in a Cooking Pot.
Mount the Lynel, typically after an arrow to the face to stun them, and go ham with your strongest weapon before being thrown off.
Black Lynels appear only in the Treacherous Tower in A Link Between Worlds, on the 49th floor of the Advanced level. They have the same amount of health and deal the same damage as regular Lynels, but have the ability to spit single fireballs in addition to breathing streams of fire.
Blood Moons most commonly appear once every 2-3 hours of continuous gameplay and, under normal circumstances, will trigger at midnight in-game. However, in situations where the game is running out of memory or assets are not loading correctly, a "Panic" Blood Moon will be triggered, even during daytime.
Four Heart Containers in each quest are missable if Link chooses the 2nd Potion instead of the Heart Container. It is ideal never to choose the Potion, as Link can buy Potions at any time. If he passes up a Heart Container, then it can never be obtained again.
If you're wanting to keep farming Lynels for their rewards, you'll need to wait until after a Blood Moon for the Lynel to respawn in the same location. Read more on Tears of the Kingdom: Zelda Tears of the Kingdom Green Tunic - get the look. Zelda Tears of the Kingdom Paraglider - location revealed.
Regardless, once you've got at least 37 essences stored in the statue, retrieve them and convert them into hearts. You'll now have 40 hearts, without losing any stamina in the process. Enjoy having 40 hearts and 3 stamina wheels at the same time!