Incredibles 2 will be about Helen Parr/Elastigirl (Holly Hunter) trying to get superheroes legalized again, and new heroes will appear to facilitate that plot.
There will apparently be 25 new superhero characters, most in presumably small roles. However, six who will apparently be more important showed up on the recently-released movie poster (albeit hard to see), and Disney has now released concept art and short descriptions of each of them.
• Voyd, the only one with a known actor (Sophia Bush), is an Elastigirl fangirl who will apparently have the largest part of the group. She can create voids that manipulate objects.
• Brick is a large, muscular woman with super strength and toughness.
• Reflux is an older man whose power is to make lava hotter, which is apparently useful for breaking into secure locations.
• Krushauer is a telekinetic, and apparently quite good at it, as his description says that he can crush a car without touching it.
• Screech looks like an owl, and made himself some wings to complete the look, and has a super-sonic screech.
• He-Lectrix can shoot lightning from his fingers.
These wannabe heroes apparently all work at DevTech, the company that employs Helen in their quest to end the ban on superheroes. Given that she is a retired pro from the days when they were legal, one can expect them all to look up to their new co-worker. (Director Brad Bird compares Voyd to an over-affectionate dog.)
The Parrs and family friend Frozone (Samuel L. Jackson) were the only superheroes developed in the first movie, so it will be interesting to see what these new characters can bring to the sequel’s story.