Publications of the Modern Language Association is probably the most prestigious peer-reviewed journal for English (and other language) literary studies. Nevertheless, Researchgate underestimates PMLA and other high-impact journals, while overvaluing other journals. I do not know the source of the Researchgate criterion for impact.
Depends on what your research is... The Johns Hopkins University has Eighteenth-Century Studies and its British counterpart is the Journal for Eighteenth-Century Studies (JECS). These are really prestigious. There are others but you should maybe specify what kind of research you are talking about : )