If you can add too or correct this list contact DN

Adalbertus        -   Albert or George
Aemilia             -   Emily
Albertus           -   Albert
Aloysia             -   Louise or Louisa
Aloysius           -   Aloysius, Alex or Lewis
Anastasia         -   Anastasia or Nancy also Statia or Stacia was a nickname for Anastasia
Andrea            -   Andrew
Antonius          -   Anthony
Appolonia       -   Polly or Pauline
Blasius            -   Blase
Caritas            -   Charity
Carolum          -   Charles
Carolus           -   Charles
Deodatus        -   Theodore
Dionisius         -   Dennis
Eduardus        -   Edward
Egidius           -   Gideon
Elizabetta       - Eliza, Elizabeth, Lydia, Lisa
Estella            - Estelle, Stella
Fidelia            -   Vera or Faith
Gottfridus/Godefredus - Godfrey
Gratia             -   Grace
Gualterus        -   Walter
Guilhelmus      -   William
Henricus         -   Henry/Harry.
Henrietta         -   Henrietta or Harriet
Hieronymus     -   Jerome
Honorah          -   Nora/Norah.
Hugo               -   Hugh
Iacobus           -   James or Jacob
Jacobus           -   James or Jacob
Johanna/Jonna -  Jane, Joan or Jean
Joannes           -   John
Katharina        -   Katherine, Catherine, Kathleen, Kate
Laurentium      -   Lawrence
Ludovicus        -   Louis
Magdalena       -   Madeline
Marcus             -   Mark
Margaretta        - Margaret, Marguerite
Martinus            -   Martin
Matthias            -   Matthew
Matthaeus         -   Matthew
Maria                -  Mary,  May, Mae, Molly
Michaelem         -   Michael
Nantia               -   Nancy
Ni                     -   Nicholas
Patritius             -   Patrick
Samuelem          -   Samuel
Seraphina           - Adelaide, Joyce
Theodoricus       -   Derek
Theodorus          -   Theodore
Veronica            -  Veronica or Bernice
Vitus                  -   Guy

A Large List of Latin Names

Eugene - for Owen - found this in my own family & referenced in Tracing Irish Ancestors (A Roberts Pocket Reference) by Maire Mac Conghall and Paul Gorry.

"Interchangeable Forenames: In Ireland many of the variations occurring in regard to forenames were brought about by phonetic translantions of Gaelic names into Latin or English.  For instance, Brigid was latinised as Bedelia (possibly because of the pet form Biddy) and subsequently Delia.  Brigid and Delia were regarded as the same name and used interchangeably even into the 20th century.  Other examples of this type of quasi-translation are Owen (originally Eoghan) to Eugene;  Brian to Bernard;  Gubby (Gobnait) to Abby (Abigail) or Deborah."

Others from the book:

Anna = Anne
Cornelius = Cornelius, Conor, Neil
Demetrius = Jeremiah (Demetrius is a latinised from of teh Gaelic name Diarmaid which had been incorrectly anglicised as
                    Jeremiah, Jerome, Jerry, Dermot, Darby
Honoria = Hannah, Nora, 'Norry'
Nigellus = Neil
Timotheus, Thaddeus = Timothy, Tadhg, Thaddeus, Thady

Kathryn M. Doyle

Domina means Mistress in Latin cf
Dominus Master or Lord