When I was working in nursing homes, I was doing country and pop from the 50s through the early 90s. As Don mentioned, there are certain songs and artists that seem to please just about everyone and I did many of those in every facility. Some of the artists that come to mind are Elvis, Kenny Rogers and Hank Williams sr. Some songs that always went over were "Rose Are Red" by Bobby Vinton ( a favorite of the ladies that make up 90 % of the residents) and "Raindrops" by BJ Thomas.

But you eventually get to know the facility and go from there. At a memory care facility, you could be playing "Comin Round the Mountain" and similar songs and going over well while some places wanted straight country. Of course, you could get sing-a-long type song requests anywhere. I got a request for the Rolling Stones in one place and that shows the breadth of the type of songs people in these places will like since ages run from 60 (or younger) to 100. I had one lady that always wanted "San Francisco" and she lived to 102.