I've been contemplating the idea of a Digital Type...and eh...I'm a bit wishy-washy on it. Perhaps a Cosmic/Space Type? It'd definitely cater for Pokemon like Solrock, Lunatone, Deoxys, the Cleffa line, Starmie, Jirachi etc.
Solrock - Cosmic/Rock
Lunatone - Cosmic/Rock
Deoxys - Cosmic/Psychic
Cleffa line - Normal/Cosmic
Starmie - Water/Cosmic
Jirachi - Steel/Psychic/Cosmic
Palkia - Cosmic/Water/Dragon
Meloetta Cosmo Form (new form) - Normal/Psychic/Cosmic
Maybe this is what the typing could be for the older Pokemon.