The ones that weren't gutted that much by new player experience and in turn become idiot-proof ride, because some clown at arena got some serious telemetry in which he saw feeding cow with hay being "too confusing".
Any heart that has enough compatible events nearby that made pumping progress faster. And also these that aren't limited to one particular task (because of npe).
With this relic thing they baked for SotO, I wouldn't be shocked if in further expansions they'd bring fetch quest in some form