Note: this is intended to be a canonical question about whether or not a spell or ability targets so there are multiple sub-questions.
Can Hexproof or Shroud save my creature from Wrath of God? What about a Cyclonic Rift that was cast for it's Overload cost?
Does shroud prevent me from using the Monstrosity ability of a creature, or from giving it more counters with Proliferate?
Can I cast an Aura Enchantment on one of my creatures with Shroud, or an opponent's creature with Hexproof? Or can I use the Equip ability to attach an equipment to one of my creatures with Shroud?
Will Diffusion Sliver's ability trigger when my opponent plays Wrath of God? And will I have to sacrifice my Phantasmal Image if my opponent casts Nausea?
Will Shroud or Hexproof prevent an opponent from choosing me with Stuffy Doll's ability?
Will Hexproof keep one of my creatures from being affected by Sleep?
If an Aura or Equipment is attached to a creature with Hexproof, does the Hexproof protect the attached permanent?
Can Redirect change Burn Down the House to only target a single creature instead?