Those serving a meal should be allowed to eat: Pesachim 107b
Leaving food on one's plate, so that the workers will get to eat it, rather than leaving the food in the serving vessel: Eruvin 53b
Not leaving foods with a strong smell or sharpness in front of workers who aren't allowed to eat it, to avoid causing them pain: Ketuvot 61a
Avuha bar Ihi and Manimin bar Ihi had wait staff. One of them gave the staff food from one dish at the start of the meal to sate their appetites; the other gave from each dish as it came out. Eliyahu would come speak with the latter one: Ketuvot 61a
