So I know there is such thing as custom rabbit hole career's like the waiter career from NRaas but is there any such thing as custom professions? What I mean incase you are confused are jobs that are kind of like the firefighting profession where you get to go to work with your sims and by custom ones I mean are there any mods that people have made for different types of jobs? For example, a tattoo artist profession since Ambitions only came with the stylist or a barista profession where your sim works as a barista at a java hut lot! Now I'm not looking for rabbit hole careers for these types of jobs so this is basically a yes or no answer. with these, I just want to know if there are any and if not is it possible for these to be created because in the future this might be something I'd like to play around with when I get better at making mods

These sim positions you are describing are not professions, they are Role Sims and are not as they exist today intended to be taken up by the actively being played household. A tattoo artist or a barista, for example, doesn't progress in those roles. They just go to work every day (all 7 of them per week) and often have to work ridiculously long hours to staff their assigned role object. These sims can be homeless or inactive residents and can earn a living wage by way of NRaas Register, but they don't have real careers or professions.

I think what you might be after is something more along the lines of Zerbu's Ultimate Career mod, or at least this is as close as we can get with TS3. It's more of Do It Yourself kit for playing sims in what would otherwise be strictly rabbit hole type careers.
http://nraas.wikispaces.com/Zerbu%2...ate+Careers+Mod

Well if you wanna fiddle with it, the only thing close to a custom profession i have seen besides zerbu's ultimate career that was mentioned above is the mangaka career by Arsil : http://modthesims.info/d/579441
I believe that this idea has a lot of potential..
A scripted object that bounds the skill you want and just reports to a rabbithole progression whenever you want but honestly not sure if it would work with inactive sims.
I could totally see a political career for example with the setup Arsil used..
Bound on a podium object with the charisma skill in use , i think the possibilities could be endless.. or not, i wish i knew how to script just to take advantage of his/hers idea.
Anyways hope you'll/create find what you' want.
Have a nice day ^^

Sorry it took me forever to read this,

But I know they are roles what I meant by this is there any chance these roles can be turned into professions that active households can play?

Here's more custom careers - haven't tried them myself, as yet, but maybe there is something you can use?
https://missyhissysjobcentre.wordpr.../the-job-board/