Every once and a while you want to send your sister a heartfelt gift to say boldly and unabashedly: I care and I miss you. That’s when sister mementos are the only gifts that will do, trinkets or traditional items that get sentimental and decidedly mushy, but say loudly and clearly that you love your sister and wish you could spend more time with her. No matter what, she’ll love your straightforward sentimentality.