The Dutchman will take over at Old Trafford after the Netherlands' FIFA World Cup campaign as he seeks to turn United around following a dismal campaign last time out.
Under predecessor David Moyes, United finished seventh and relinquished their Premier League crown.
De Gea feels Spain team-mate and Barcelona midfielder Iniesta would serve as a major boost for the champions, should Van Gaal opt to sign him.
"(If I could) I'd sign Iniesta," he told Movistar.
"I'd bring him to United because for me if he's not the best player in the world, he's one of them.
"He has personality, lots of quality, a goal in him. He's got everything."
In terms of potential outgoings, De Gea also stated his desire for Juan Mata to remain - with the former Chelsea man contributing six goals in 15 appearances after joining midway through a turbulent season at Old Trafford.
"I wouldn't sell him," De Gea explained.
"We have that extra bit of quality with him, he's a great player and has fitted into the dressing room really well.
"People love him and in my opinion he’s a really important player."
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