I’m not sure if DC is planning to release multiple previews for the various stories in the upcoming Flash #750, but they’ve posted two sneak peeks thus far. You can see three textless pages of a story by Marv Wolfman and Riley Rossmo at Newsarama, and Nerdist has several preview pages from the story by Francis Manapul and Brian Buccellato. It’s possible there’ll be more pages released in the coming days, since the issue is due out next week.
Regardless, it’s going to be a big issue! There are themed variant covers for every decade of Flash history, and several stories by many former Flash creators; don’t forget the Geoff Johns and Scott Kolins story too. Hopefully there’ll be something for everyone.