Thank you for sharing this
I would also definitely like to see the option for custom categories/templates (for personal), however I understand there are technical issues to do this. One simple workaround would be to create an item with some custom fields and save these as favorites. However this falls flat on its face because, as pointed out by mickael, you can't have multiline custom fields, and there are any number of custom items I'd wish to add that need multiline data. Surely this can't be a big technical issue. Notes is multiline, Software category License Key is multiline. Where I click to create a new custom field and get offered Text,URL etc, offer a Multi-line Text option.
Thanks for the feedback @ddk. We have mentioned the desire for multiline custom fields to development, and perhaps that is something we can offer in the future.
+1 for SSH keys
+1 for GPG keys
+1 for x509 certificates
Thank you for letting us know you would like to see this @danielwagn3r