Xp Ore by vottomatic1319
Adds XP Ore to Minecraft!
Xp Ore by wombatty, MCreator
Adds an XP ore and Recipe to craft XP Bottles.
Xp Spawner Control by bright_spark
A mod to control the experience dropped by mobs spawned from mob spawners
Xp Storage by BrickMaster5000(SteveBeeblebrox), MCreator
Store your Xp!
Xplosion Core by Big_Xplosion
A core for all the Xplosion Mods
XrayBlock
This Mod adds in a Simple feature which is an X-ray Block that allows you to see through Walls, Ground, Bedrock, And Caves. Crafting Recipe on the Forum post
Xtones by TehNut, Dhvagra, InsomniaKitten
Xtones adds modern/futuristic/fantasy style decorative building blocks.
Xtra Armour Mod
This mod adds armour such as Dirt Armour, Cobblestone Armour, Sand Armour, Gravel Armour, Invisi Armour and much, much more.
Xtra Crafting Recipes by Caleb, MCreator
Xtra Drinks by Strikeboom, ChauhanSai
Venture into a new world with XtraDrinks. This mod adds new fluids into the game with a new mechanic, dehydration. Explore new structures and craft new foods around the world. You can become the master liquidor. Has support for Tinkers Construct and JEI
Xtra Tools by 2MuchMinecraft
Adds extra tools and ores!