Utility Ores is a mod that adds ores for some of the items in the game and generates them underground.
Why go to the nether when you can go mine the Nether ore, Glow ore and the... Blaze Ore! No need play around with blazes anymore, just mine the ore and it will give you the drop. In addition to that there is also an Ender ore to make things a lot easier, instead of fighting those Endermen. To make things even better-er there is a Ghast ore, which will give you ghast tears.
Trouble finding cows for leather? Well find the not-so-rare Leather ore as well as the Sugar and Bone ores and you are all set.
Afraid to go to the ocean temple? You can find the Prismarine ore for your decorations.
The mod will most likely not be updated on this site, or have late update pushes. Visit http://minecraft.curseforge.com/projects/utility-ores to be up-to-date with the mod.