I need to make pancakes for 8 people tomorrow.
What's a decent temperature to keep them warm in an oven for 10-20 minutes until I'm finished with all?
Use the ovens "Warm and Hold" feature if it has it until you're done. Otherwise, the ovens lowest temp like 170°F I think.
If it's only for 10-20 minutes I wouldn't bother with the oven as it might dry them out.
I would put the pancakes on a plate and put a lid over the plate. The lid combined with adding fresh pancakes should help retain the heat and moisture.