Hey @freedy82 and welcome to the Cockpit community 
I have never faced such a requirement, but I think custom fields in combination with the documentation about fieldtypes might be interesting to you.
As far as I can tell, this still won’t allow you to make a “Year picker”, but you could create a select field with all available years by using “Multipleselect”. Definetly not the perfect way, but maybe a workaround.
@admins Just wondering. The docs say that the Date picker is “based on Spectrum.js”. But Spectrum seems to be a color picker. At least from what I have found. Is this a typo? 