Sure, they're included in "lot's of ways"
But if you want to measure all power lines of a PC without turning it on and off repetedly, I think a homemade cable with measuring resistors is the cheapest and easiest way to go...
- make cable
- insert cable
- boot PC and start program payload
- measure voltage drops
- turn off PC
- calculate current for each voltage
- A multimeter would be either risky or time consuming, if you're referring to using the current range and either hold the leads in place by crocks or connect it up properly (you still need the meter to measure the resistors I mentioned however, but it's so much easier to connect to them, since loosing contact woldn't mean a thing).
- A power supply is what's being measured, but on several lines.
- A current sensor, hey that's the resistors, but if you think off current transformers, they would be expensive compared to resistors, especially since it's DC lines, so linear Hall current transformers are needed.