"Generation Shift" will work extremely well in a "Crystal Beast" deck, since it says 'destroy' not 'Tribute' and so moves your chosen Crystal Beast to the back row, and gives you another.
This card works well with "Sacred Phoenix of Nephthys". Destroy "Sacred Phoenix of Nephthys" to bring out another "Sacred Phoenix of Nephthys". During your next standby phase the destroyed "Sacred Phoenix of Nephthys" will return to the field, activating its effect.
This card works well with "Harpies". For example, if you have "Harpie Lady" on your side of the field, you can activate this card to summon the more powerful "Cyber Harpie Lady", whose name is treated as "Harpie Lady".
This card works well with "T.G."; chain it to your opponent remove from play or steal effects. Not only will you trigger your "T.G." monster's effect, you'll gain another copy of the monster in your hand.
This card can work well in an "Amazoness" deck. With "Amazoness Village" and any "Amazoness" monster on the field. you can use "Generation Shift" to destroy an Amazoness monster and add the same one to your hand then use the effect of "Amazoness Village to special summon any Amazoness from your deck with an equal or lower level.
Destroy Yubel with this card to bring out Terror Incarnate or Terror Incarnate to bring out The Ultimate Nightmare.
This card works well in a Kozmo deck, to destroy a Machine-Type Kozmo monster, adding a copy of that monster to your hand, and triggering its effect to banish it and summon a Psychic-Type Kozmo monster, possibly during the battle phase for maximum damage.
This card works extremely well with Pendulum Monsters, because you can just keep bringing them back again and again.