I am looking for a brief list (with some English, not Hebrew-only) of which selichot Ashkenazim say, on which days. If I understand correctly, most Modern Orthodox Ashkenazi Jews basically follow minhag Poland (Polin). (So far I have only found lists for Sephardic or Chasidic minhagim.)
It’s unclear from the question itself, but since you tagged this elul, I assume you mean the selichos said during the last week of Elul? In that case, my Artscroll Nusach Lita seems to be the volume you’re looking for.
The volume numbers the Selichos 1-100. In their Table of Contents (p. IX-XI) they have all the Selichos ordered by day, and they also have them listed in alphabetical order (p. XII-XIII). Do note that, especially on the longer days, many congregations skip one or more of the Selichos, but which one(s) varies from congregation to congregation. Also note that this list does not account for pieces which are said every day, like Machnisei Rachamim, so you may want to flip through each day to get a feel for the general proceedings.