Next Avengers: Heroes of Tomorrow (2008) on Netflix

Plot summary

After Ultron and his machine army defeat the Avengers and take over the world, Captain America asks Tony Stark to hide the Avengers' children above the Arctic Circle. Stark raises James, Torunn, Azari, and Pym at the refuge, training them to use the abilities passed down from their parents. Twelve years later, Vision arrives with word that Hawkeye's son has been found. While the children listen in, James triggers a set of robots called the Iron Avengers, which Stark built to resemble their parents. The robots launch themselves at Ultron. Ultron's forces then trace them back to the refuge, forcing Stark to put on his Iron Man armor so the children can get away.