Act of Treason, Goatnap, Hijack, Kari Zev's Expertise, Mark of Mutiny, and Traitorous Blood are all pretty much the same effect, Mark does have the added benefit of putting a counter on the creature, so you only need Marchesa and a sac outlet for it to steal something permanently
The best steer we have is that Wizards now tries to place bans in the first few weeks after a new set releases - so checking the release dates can provide a good guide
Enchanted creature loses all abilities and is a green Elk creature with base power and toughness 3/3
Make a Treasure token if you have the initiative, make three if youve already completed a dungeon
Pyromancers Goggles provide some mana acceleration that can also do crazy copy things with our red spell
Well, in 1v1 Magic at least, its unlikely to be the latter