Goose fat makes a nice roast potato, but is fairly expensive (I bought some in Normandy last months much cheaper than here).
Beef dripping also makes an excellent roast potato and is good for browning cow for a casserole or pot roast.
I always do my browning in small batches in a heavy iron pot and let the fat drain off before finishing. I eat very little fat as I have plenty already and mostly use olive oil.
BTW I use a modified Delia method for roast potatoes and roast vegs, browning them one at a time in very hot deep fat instead of putting them in a great oven pan to get greasy.