Doubles is quite an interesting format. Unlike Singles, 4 Pokémon are taken to each battle, and the format is usually seen as the most fast paced one. It is also the common choice of the Pokémon World Championship.

Doubles has a few differences to Singles, for example Protect. Protect is seen as a niche but not crucial move in Singles, however is an immense staple in Doubles. Moves such as Stealth Rock and Toxic are also seen less, as the format's speed renders these moves as less of staples. Here are some examples of moves that are extremely important in Doubles.

Tailwind / Trick Room

Tailwind and Trick Room are insanely common moves in Doubles, as they can instantly change the pace of a game. Trick Room reverses the order of play for 5 turns, meaning slower Pokemon will attack before faster ones NOTE: priority is not effected.Tailwind doubles the speed of your Pokemon for 4 turns. These moves can make Pokémon like Amoonguss become faster than a stabbed rat and Spore the world.

Protect

Protect is much bigger in Doubles as it allows one of your Pokémon to dodge a potential attack. Strategies such as using Trick Room on one Pokémon and protecting the other allows for your protected Pokemon to survive so they can utilise Trick Room more effectively. Strategies like "double-protecting" are also seen.

Multi hit moves + Wide Guard

Moves such as Earthquake, Rock Slide, Water Spout, Eruption are all generally good moves to use in Doubles. Hitting both Pokemon for "chip damage" is essential and most are quite powerful. Wide Guard, however, blocks all of these attacks and stops them in their tracks. However Wide Guard is quite an uncommon move so those who have it are known for the move, so don't usually perform the role as effectively as they could (Aegislash)

Follow Me / Rage Powder

These two moves allow the user to redirect any move to themselves. This allows sweepers to set up, and defeat the opposition. A famous example of this is the VGC14 winner Se Yun Park who used a Pachirisu to redirect with Follow Me. NOTE: this does not redirect multi target moves