Actual Amiga industries are only A-Eon, ACube (hardware), and Hyperion (OS). You are free check if they need some personnel.
Also there is Individual computers by Jens Schönfeld. it is a one-man company, but if market of Amiga will expand at any time, he could ask for some collaborators in the future.
There are two or three main stores selling Amiga products, such as Vesalia and amigakit.com. Also they could be checked if they need collaborators.
Ares Shop is specialized into building PC Intel and ARM computers and sell them bundled with AROS hosted on Linux (AEROS operating system) builds for it. You may check (again) if they are searching for collaborators. You must be skilled in Intel + Arm + Motorola 68K programming though.
shttp://www.ares-shop.de/
The only remaining industrial software firm selling for Amiga is PageStream LLC. but Amiga is only a marginal market for them, and I think you need multiple skills in programming PC, Mac and Android first, to be hired by them. Pagestream for Amiga is developed in they spare time as they still love our platform.
There is MorphOS Team selling MorphOS operating system. They are a group mainly based in Germany, and you may prove to have really skills to enter their team, and making MorphOS is only a spare job for them, with scarce renevues at the moment.
Also you may join anytime AROS team whose people work free as AROS is Open Source, but you may earn money by asking community donate for bounties that will pay your coding work.
For any other career you may become an Amiga Developer and sell your software thru centralized store AmiStore kept by A-EON.
Any customer can purchase your software thru store and money will be sent to you. But don't expect being rich with that job.
At least it Amiga does not raise a bit its userbase.
But sure if you will develop good software this could convince other people joining Amiga scene enlarging market and consequently new software request.
That's all ATM.
