The most popular digital card games are tie-ins to physical TCGs or extremely popular video games and movie franchises
Timing restrictions based on the card's type are ignored, but other restrictions (such as "Cast [this card] only during combat") are not
Third Path Iconoclast Balmor, Battlemage Captain Sprite Dragon Baral and Kari Zev Zaffai, Thunder Conductor Lore Drakkis Gelectrode Guttersnipe Stormchaser Mage Young Pyromancer Izzet Chemister Goblin Flectomancer Veyran, Voice of Duality Hypersonic Dragon Big Creatures Another curious departure from the colors of mad science, Izzet's experiments don't typically result in giant monsters
As noted by Kotaku, new waves of Pokmon cards tend to ramp up in value, before falling fairly sharply back down to Earth
There are also options for making digital back-ups of physical games and playing them with more convenient emulation software or devices
There are plenty of small details that might seem insignificant, but could actually be the difference between a card being worth a few bucks or the down payment on a new house