Taking Dualtach because it sounds like a software company and Dimma because it sounds more feminine to me.
Take two:
Daghan (Dagawn)
Daigh (Day)
Daighre (
Dara)
Daimhin (
Davin)
Dalghach (Dovlock)
Deaman (Daman)
Diarmid (
Dermot)
Dubhda (Dowd)
Duarcan (Durkan)
Donncuan (Dunkooan)
Donnchadh (Dunnaka)
Daibhi (
Davey)
Daithi (Dahy)
Dianach (Deeanock)
Diochu (Deekoo)
Domnall (
Donal)