Unff I really love having a piano and Wurlitzer play together. Usually harmonizing with parallel 3rds/6ths/whatever, but occasionally octaves or unison too. Obviously it depends on the context and mix and whatnot, but usually if the piano plays the higher line my brain hears it as “piano but slightly crunchy” and if the wurli plays the higher line it sounds like “wurli but mellower and with more depth.” Y’all should try it!
Overall I just really love pairing random instruments to see what kind of sounds they make together. Like maybe I’ve said this before but sometimes I’ll add bassoon to thicken synth pads. Man. Music is so cool.