I always carry one of the Swiss Army Knife mini's:
All the implements get used quite a bit, and too small to irk the guards at my building's entrance. And even allowed on planes again. When traveling, I like to seal our suitcases with small zipties; can use the scissor to cut them open at destination. Though in the early days of TSA, I had to forfeit 2 of these because I forgot they were in my pocket.
