Water Bottle + Nether Wart → Awkward Potion
Water Bottle + Fermented Spider Eye → Weakness Potion
Awkward Potion + standard vanilla ingredients → effects such as Speed, Strength, Healing, Poison, Regeneration, Fire Resistance, Water Breathing, Night Vision, Turtle Master, and Slow Falling
Redstone extends supported potions
Glowstone strengthens supported potions
Fermented Spider Eye corrupts certain potions, such as turning Night Vision into Invisibility
Gunpowder converts a normal potion into a splash potion
Dragon's Breath converts a splash potion into a lingering potion