I’ve no idea what those first 2 are but: if the names were in purple, green or white you can get them from a normal gold pack. If the name was red or orange it means they were either epic or legendary which means you’ll have to draft or get a platinum, diamond or mystery pack. As for “To Battle!” and “Unleash Hell”, I believe they are only available from the premade decks BUT “Calm Before the Storm” and “Darken the Sky” have the same effects (copy the next played melee or ranged attack respectively) and both of those can be gotten from drafts, gold packs or brawls (check the brawl loot table thread on the game’s forum for which exactly) so unless you want a lot of the other cards in those decks you don’t need to buy them.
It’s worth noting that they do also add +2 to one of those attacks when it’s played, but they also don’t seem to stack if you play them multiple times before another card like CBtS and DtS do (though I did play a Cbts then To Battle and get 3 plays of my next melee card with one of them being at +2 but still, at that point you just have to ask yourself how much do you really need to and will you be able to stack those attacks in most fights brawls included.)
EDIT: Epics and Legendaries are more rare than "Rare"s for a reason so it’s not surprising if you haven’t seen something in a draft. Odds are if it’s not something found on the crafting screen then it’s either a brawl loot or draft pick.