MDFCs Some of these are better than others, sure
The "My Cards" search function allows players to search their cards by favorites, rarity, Pokmon type, and much more
However, it can lead to just a handful of decks becoming dominant, able to beat any other decks they face - and thus the game's overall scene (often called its 'meta') becomes very samey, as everyone is forced to play with similar decks and cards if they want to have a chance of winning games
This support card allows trainers to put a Mew ex in the active spot into their hand, which is pretty meh
Battles enter the battlefield with a number of 'defense counters' which work just like loyalty counters, and they go to the graveyard when their defense is depleted
If the attacking monster's ATK is equal to or lower than the DFD of the defending monster, the difference is deducted from the LP of the controller of the attacking monster, and neither monster is destroyed