My go-to’s are PLOS ONE and Palaeontologia Electronica (side note: I feel like the journal should officially change the name, as so many people add an extra “c” at the end of Palaeontologia – it is a super common error!).
When I taught geology at the university level, I frequently incorporated peer-reviewed publications into assignments. I’m curious to learn how K-12 teachers might do the same. Perhaps @groberti could give some insight, as she crafted a high school lesson plan that did this (https://www.myfossil.org/paleontology-in-the-real-world-using-the-recent-paleontological-literature-to-engage-high-school-students-and-encourage-stem-based-learning/).