Original OG content curated by M.T.S. (thanks!); since added & edited content.
A bene placito - At one’s pleasure
Ad astra: To the stars
Ad augusta per angusta - To high places by narrow roads
Ceteris paribus - All else being equal
Cum grano salis - With a grain of salt
De nihilo nihil - Nothing comes from nothing
Deo volente - God willing
Docendo discitur - It is learned by teaching (Seneca)
Dum spiro, spero - While I breathe, I hope (Cicero)
Ex animo - From the heart (sincerely)
Fortitudine vincimus - By endurance we conquer
Habetis bona deum - Have a nice day
Hic et nunc - Here and now
In casu extremae necessitatis omnia sunt communia - In case of extreme necessity everything is common (paraphrased Latin adage: Everything is common.)
In cavda venenvm - In the tail poison (Watch out for what you don’t see)
In medias res - Into the midst of things
In totidem verbis - In so many words
Gelatus - Frozen; gel; gelatinous (ge-latin-ous, heh);
Justitia omnibus - Justice for all
Liberae sunt nostrae cogitationes - Our thoughts are free (Cicero)
Maximus in minimis - Great in little things
Ne quid nimis - Nothing in excess (Terence)
Non scholae sed vitae discimus - Not for school but for life
Pactum serva - Keep the faith
Paucis verbis - In a few words
Pax et bonum! - Peace and salvation!
Pax tecum - May peace be with you (singular)
Plusque minusque - More or less
Pro nunc - For now
Propino fibi salutem! - Cheers!
Requiescat in pace (RIP) - May s/he rest in peace
Salve sis - May you be well
Totidem verbis - In so many words
Uberrimae fidei - Of the utmost good faith
Vade in pace - Go in peace (Roman way of saying goodbye)
Veritas numquam perit - Truth never perishes (Seneca)
Veritas vincit - Truth conquers
Vincit omnia veritas - Truth conquers all
Volens et potens - Willing and able