Both Maguire and Vardy will hope to play a part when England open their tournament against Tunisia on Monday night.
Gray, who is an England Under-21 international, has paid tribute to his Foxes teammates, and has backed the Three Lions to "have a very good tournament".
"Obviously you've seen how Harry plays, he's good on the ball and he's confident. He's a solid defender," Gray told Sky Sports News.
"Jamie just loves to score goals and that's what he's done for us this season. He's done a lot for us in a lot of games this season. So collectively as an England squad I think they've got a good balance and I think we could have a very good tournament."
England will take on Tunisia, Panama and Belgium in the group stage of the competition.