Molotov Cocktails
Lara encounters Molotov Cocktails in several Levels of the 2013 reboot game. Also, they are a weapon she can craft in the follow-up, Rise of the Tomb Raider.
Tomb Raider (2013)
There are miscellaneous Enemies that throw bottles filled with burnable liquid at Lara. Unlike Dynamite sticks - which can be shot out of the air - Lara can only evade these, or else they will burst open on impact with the ground and seriously injure her.
Molotov Cocktails are mainly used to draw Lara out of hiding so she can be shot by attacking Solarii after she left her cover.
Rise of the Tomb Raider
In Rise of the Tomb Raider Lara can create her own Molotov Cocktails. She has to find and pick up Bottles and combine them with Cloth (hold down RB during combat).
Molotov Cocktails are a fairly efficient way to get rid of several Enemies at once: Trinity patrols often stand together in smaller groups; a well placed Molotov Cocktail will burn all of them.
Molotov Cocktails are also a possibility to burn certain cloth covered barriers or even the Posters of the Difference of Opinion Challenge, as Lara has not yet found the Oil Flask she needs for crafting Fire Arrows at this point in the story.