Paperless Post - Paperless Post is an online platform for creating custom card and invitations.
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Pingg - Pingg is an online e-cards and invitation maker and invitation sending platform.
Sketch - Professional digital design for Mac.
Manvite - As the name of this service suggests, the users can avail easily and simply invite rather than online summons that are blessed with flowery fonts and dabbling champagne glasses.
Affinity Designer - Professional creative software, exclusively for Mac.