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The background of the card is done in a more traditional style, with the water being reminiscent of The Great Wave off Kanagawa
For example, a creature that enters the battlefield with one +1/+1 counter on it will still receive a +1/+1 counter, and Leyline of the Void will still exile creatures that would die
Finally, a listing of all sets and their set symbols may be found in the Researching Tower here: Images of all legal cards may also be found there
Both of them do a good job of showing up the expansions new mechanics and key features, and after playing them I dont think a third one would have been necessary, especially because it would have just been another Ruby/Emerald like last time
The monster that appears on the Soul Burn card greatly resembles a creature from Dungeons & Dragons called a Drider