All talk to the contrary (and you all know who you are!), the Sony A7 series cameras are the greatest cameras that modern ingenuity has ever or ever will create and within the next few weeks all other cameras manufacturers out of a sense of embarrassment will recall all these other unworthy devices and voluntarily consign them to the ash heap of photographic history and start manufacturing political bumper stickers instead.
Nevertheless, there are attachments that crop up between photographers and lenses that cannot be severed because of changing camera brand or mount type. Lenses so awesome that you intend to have them interred with you like some kind of Egyptian pharaoh or Bronze Age warrior king in the untimely event of your demise. Can you name any lens that because of inherent virtues you will never part with no matter what camera you shoot? This even includes lenses that cannot be attached to the A7 cameras (but is not restricted to these).
I'll start this with my own humble manias.
Sony 135 f1.8
Minolta 200 f4 macro