You can get them from trades with Bill(Ishihara) after he appears, and can possibly trigger a new trade if you talk with a specific NPC in each of the Pewter/Fuchsia/Cinnabar Clubs(Rock/Science/Fire)
The main ones in the format are Howling Mine, Jayemdae Tome, Jalum Tome, and Book of Rass
Creatures with deathtouch lessen an opponents desire to block so that they can keep their best creatures, which means you have the potential to accumulate the number of poison counters an opponent gets from infect or toxic creatures
If a replacement effect causes a player to exile the top four cards of their library instead of putting them into their graveyard as Gyruda's triggered ability resolves, the creature card you choose may be one of those cards in exile
They break down your cards condition into four key areas: centring, corners, edges, and surface