St. Thomas Aquinas wrote several beautiful hymns for the Office of Corpus Christi. The last two verses of each got turned into mini hymns that are frequently used.
Pange Lingua yields "Tantum Ergo" at the end. Verbum Supernum has "O Salutaris Hostia" at the end. Lauda Sion Salvatorem has "Ecce Panis Angelorum" at the end. And then there's Adoro Te Devote.

Remember the story? Another man had written hymns for this Feast, and when he saw St. Thomas Aquinas' entry, he destroyed his own. Indeed, these hymns are borderline inspired. Totally out of this world, in a class by themselves. Look at the solid doctrine in each stanza, how they rhyme IN LATIN, how elegant they are, yet how easy to sing, etc. The man was a holy genius.

The chant for Lauda Sion Salvatorem is remarkable in that the melody changes every 2 verses -- and it's a long hymn! So many choirs/singers/scholae have difficulties, at least at first. A lot of practice is required to master it. Not that the chant doesn't hang together or doesn't have a catchy melody -- it's just that you have to learn so many melodies before you can confidently sing the whole thing without errors. My secret: getting a copy of this hymn by the Schola Bellarmina. Highly recommended.