If youre not already playing a Karador, Ghost Chieftain deck or something with reanimation, Idol of Endurance offers you a little taste of the style
If an Adventure spell leaves the stack in any way other than resolving (most likely by being countered), that card won't be exiled and the spell's controller won't be able to cast it as a permanent later
You get two options and both of them are great: either an enormous army of vampires, or a 10,000 power/ 10,000 toughness dinosaur, with trample, that spawns in already attacking one of your opponents
(4/17/2020) If you reveal a companion outside the game, for as long as it remains there, you may pay any time you could cast a sorcery (that is, you have priority during your main phase and the stack is empty)