I will not send cards or buy gifts to anyone at the company, to me it is unethical. If my work depends on giving a gift to a dispatcher or manager, then it is not a company I want to be part of.
I do write letters of thanks or praise for work well done, even for forklift drivers who are careful loading my truck. The letter means more to someone than a gift they only see.
In the case of the forklift driver, she was new and didn't listen to her co-workers when they told her to rush to load my truck. These guys were banging into the walls of the other trucks, but she said it is my truck and she respects my property. I wrote a letter to the CEO of the company thanking him for hiring her and told him the story, she got a raise for her diligence and the last time I was there she got a promotion.