RDA = rebuildable dripping atomizer.
RTA = rebuidable tank atomizer, the bottom coil kind
Genesis/RDTA = rebuildable tank atomizer, the top coil kind
RBA = Rebuidable atomizer (a catch all term that covers all types of rebuildable atomizers)
They are the atomizers themselves.
And they only use coils you make yourself.
So you need some wick and wire. 28g kanthal and japanese organic cotton would be a good start imo.
And some other building supplies would help out greatly. A "ohm-meter".
A coil jig (Kuro coiler, coil master). Some side cutters.
Maybe look into getting a whole set like this?
Coil Master DIY Kit V3 - Coil Master
That would be more than enough.