Nigella perhaps? Easy to look after pops up in unexpected places and once you've got it you've got it forever!
I have a number of plants that have been given by friends or by OH or that I have bought with present money. It is interesting but these plants seem to have special meaning, particularly stuff my father in law gave me, as he was probably the person I learned most about gardening from and he is no longer with us.
I also have great fondness for plants which I might accidently collected the seed from whilst visiting other gardens. These allways remind me of specific gardens and the holidays they were visited on.