Warning! This post contains SPOILERS for The Flash.A DC concept artist unveils several unused Batman suits Michael Keaton could have worn in The Flash. The Flash features updated takes on popular DC superhero suits, from Supergirl's variation on Superman's DCEU suit to Flash's sleek one-piece costume and an armored version of Ben Affleck's original Batman suit. Michael Keaton's Batman is the character with the least evident changes on his suit in The Flash, but there were still some ideas to overhaul the classic 1989 and 1992 Batsuits for the modern day.
https://screenrant.com/the-flash-batman-costumes-concept-art/