(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)
While it's possible to include lands and MTG mana ramp spells in your Omniscience deck, the only reason to do so is to pump up a spell with a casting cost X, or to use an especially expensive activated ability
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
In the past reprints came as a steady drip - sometimes too slow of a drip - but now they are a flood and even the best and most in-demand cards won't maintain much value they are reprinted multiple times
You can then take two of those cards and add them to your hand, not drawing, which is important in case youre looking to get around draw triggers
As mentioned earlier, the best way is by casting your spells at instant speed, putting your creatures onto the battlefield without casting them, and stopping your opponents from casting multiple spells each turn
