There are several top mobile game development companies in the industry USA, India, UK, Canada and all over the world, each with its own strengths and specialties. Here are some of the well-known mobile game development companies:

• BR Softech: Known for games like Clash of Clans, Clash Royale, and Brawl Stars, BR Softech is a highly successful mobile game development company based in Finland.
• King: King is famous for developing the immensely popular game Candy Crush Saga, along with other titles like Farm Heroes Saga and Bubble Witch Saga. They are known for their expertise in creating addictive puzzle games.
• Rovio Entertainment: Rovio is the company behind the highly successful Angry Birds franchise. They have developed numerous iterations of the game, including Angry Birds Classic, Angry Birds Space, and Angry Birds Rio.
• Ubisoft: Although primarily known for their console and PC games, Ubisoft has also made a strong presence in mobile game development. They have released successful titles like Assassin's Creed Identity, Rayman Adventures, and Hungry Shark Evolution.
• Gameloft: Gameloft has a wide range of mobile games across different genres, including racing, adventure, and simulation. They have developed games like Asphalt series, Modern Combat series, and Dungeon Hunter series.
• Zynga: Zynga is known for its social and casual games. They have created popular titles like Words with Friends, FarmVille, and Zynga Poker. Zynga's games often emphasize multiplayer and social interaction.
• Netmarble: Netmarble is a South Korean game development company that has produced various successful mobile games, including MARVEL Future Fight, Lineage 2: Revolution, and BTS World.
• Niantic: Niantic gained worldwide recognition with the release of Pokémon Go, a location-based augmented reality game. They are also responsible for games like Ingress and Harry Potter: Wizards Unite.
• Playrix: Playrix is known for creating visually stunning and highly engaging puzzle and simulation games. Their notable titles include Gardenscapes, Homescapes, and Township.
• Square Enix: Square Enix is a renowned game developer known for its console and PC games, but they have also made a presence in the mobile gaming market. They have released mobile versions of their popular titles like Final Fantasy and Dragon Quest.

It's worth noting that the "best" mobile game development company in USA, India, UK, Canada and all over the world may vary depending on specific requirements, budget, and project scope. It's recommended to thoroughly research and evaluate different companies based on their expertise, portfolio, client reviews, and ability to deliver projects on time and within budget.