Mometrix eLibrary This link opens in a new windowMometrix Test Preparation offers study guides, flashcards, and practice questions for over 1,800 different standardized exams including Praxis (teacher certification exams) GRE, ATI TEAS, NCLEX, HESI A2, medical technology certifications, computer technology certifications, LSAT, MCAT, GMAT, and many, many more.