Looking at an obvious example from Old School, The Deck, which runs four Jayemdae Tomes, Ancestral Recall, Timetwister, Braingeyser, and a Library of Alexandria, its a powerhouse of card advantage
Many competitive decks are filled with draw power, consistency boosters, and several copies of the same card
Both Mental Misstep and Spell Snare are opportunistic cards that you want to have open as often as possible so as to maximise their somewhat limited range of targets
Check out their official website for all of the cards, and keep your eyes peeled at your local retailer.
1st Edition cards are typically in high demand with collectors and have high price tags to boot, as these cards were only printed for a limited amount of time and are harder to come by
Bear in mind that you still cant use abilities of characters on their first turn