There are 4 different types of koi pond pumps you can choose from.
Direct drive pumps are all about power. They do cost more and wear out more quickly, but they can still provide a good flow rate even with a high amount of head pressure. Head pressure is the resistance pumps have to overcome to push water up the pipe and out into the waterfall.
Magnetic pump drives don’t use a lot of energy and they should last for a long time. But, they aren’t very powerful.
Asynchronous pumps are like magnetic pumps but more efficient and with better flow rates. They do need more maintenance to make sure they don’t break down.
External centrifugal pumps cost more but they work really well. They give more power with better efficiency and they have a long life span.
You can also find some of these types as solids handling pumps, which have great advantages: