Hello,
Grove Electromagnet is designed to be controlled by Digital port pins. The power consumption of Grove Electromagnet is 400mA and this would limit the number of such Grove can be connected to Arduino or Seeeduino boards.
Use proper power supply & Check the capacity of the regulator that is used in main board. Most of them could supply 1000mA. This limits two Electromagnets.
You could use any board as long as Grove port is available (by way of Grove Shield or inbuilt Grove connectors)
Thanks and Warm Regards.