Found some answers online but none that really matched my situation. I have one or two audio sources, and i want to find a device that can take these sources and output them to many monitoring devices, headphones, speakers etc. Controlling the source inputs would ideally be via volume knob/fader, but a source selector is also fine since I wont need both sources at the same time. Controlling the output levels should be done individually for each output channel. Ive looked around at mixers but all seemed geared for a multiple input situation with four outputs only existing on some super high end music studio equipment. What should I be looking for, does such a product exist?
I assume you want stereo outputs? There are several options. You are basically describing a portion of a monitor mixer, but you could also do it with a mixer that has a bunch of effect sends. Basically each channel has a set of "sends" that route the signal to its own discrete output. Each of these sends has it's own level control, so you can actually send a different mix of sources out of each output. These are usually mono, so you'd use one channel and one send for each side of each source in your use case.
There are far fewer of these sends available on boards these days due to the prevalence of onboard digital effects and digital outputs, but they can be found. Many boards designed for live mixing have a bunch of aux/effect sends, as do the aforementioned monitor mixers. Look at analog boards by Mackie and others and pay attention to those sends.
The easiest way to split a signal in two can generally be done with a "Y" cable so you don't have to spend much money to get two outputs from one source. Of course you can use multiple "Y" cables to get more outputs. This method doesn't have a volume control though. Headphone amps (sometimes called a jackbox) often have 4 or even 8 or 10 outputs all with their own volume control. These are also inexpensive because the hardware inside them is so simple. Note: mixing two signals into one should not be done with a "Y" cable.