There are endless contemporary versions of mashed potatoes. You could add chopped herbs or cook a few garlic cloves along with the potatoes and then mash them together. Personally, I like all of these variations, but not with meatloaf.
Meatloaf calls for plain mashed potatoes.
I like my potatoes with a few lumps, but you can beat them until perfectly smooth if you prefer. In addition, I do succumb to the contemporary twist of using part Yukon Gold potatoes when I can find them. Their gold color is so pretty and gives the effect of buttery mashed potatoes without so much butter. Adjust the butter and use yogurt or sour cream depending upon your preferences. Meanwhile, in a small saucepan, heat the butter and milk over low heat until the butter is melted.