To be removed from play (also called RFG or removed from game) is a term used to describe when a card is removed from the Duel by another card's effect. Once a card is removed this way, it cannot re-enter the current duel, except by a card that specifically allows it, like "Return from the Different Dimension".
Originally, there were not many cards which could remove other cards from play. (e.g. "Nobleman of Crossout".) However, over time, removal has become a popular theme, with several cards to go with it (Chaos and D.D. (Different Dimension) cards, for example.) And, in turn, more cards were created to bring them back (such as D.D.M. - Different Dimension Master, Dimension Fusion and Burial from a Different Dimension, for example.)
Removal is good for breaking strategies, especially when combined with a card like Fiber Jar, which reunites every player's Hand, Deck, Field Contents, and Graveyard, into a new Deck, but doesn't combine cards removed from play. Combined with monsters like Gren Maju Da Eiza, Golden Homunculus or any in the Helios - The Primordial Sun series can give a player some of the highest attack powers in the game.
Since currently, many decks rely on the graveyard, decks that rely on the effects of Dimensional Fissure, Macro Cosmos and Banisher of the Radiance, along with D.D. Survivor have grown in power. Being able to shut down an opponents Graveyard, plus having an 1800 ATK monster in Survivor that keeps returning itself every time it's removed from play while face-up for as long as the removal card is active, have shown themselves to be powerful decks.
The Removed from Play Zone can be placed anywhere on the table, as it has no actual place in the game. However, most typically it is placed above or to the right of the Graveyard Zone or placed face down beneath the graveyard.
Types of Monster Cards
Types of Spell Cards
Types of Trap Cards
Other Types of Card
ATK - DEF - Level - Attribute - Type
Playing Field Zones
Types of Summon
Types of Monster Effects
Types of Effect Monsters
Types of Spell Speed
Aqua - Beast - Beast-Warrior - Dinosaur