Some of these are more common than others. Some are catchphrases of ancient philosophers, some mottoes of universities and other organizations. Some you may have heard; some will be new to you. All of them are useful and all of them will make you sound very smart when you use them.

Ad astra per aspera

Per Aspera ad Astra "Through Hardships, To The Stars" or "A Rough Road Leads To The Stars" or "To The Stars Through Difficulties"