Looked at the list of British Butterflies, and have set a goal of adding 8 of the following to my list:

Dark Green Fritillary, Duke of Burgundy, Marsh Fritillary, Silver Washed Fritillary, Dingy Skipper, Grizzled Skipper, Grayling, Small Blue, Silver Studded Blue, and Wood White.

All are found in the Bucks/Oxford area, although most are very localised, and I'll need to travel outside of my local area to stand a chance of seeing them.