The Korg G5 is very old. I had one 20 years ago. Very hard and expensive to find. There are videos on your usual online video review outlets on it, and the V-amp. You can still get a good array of synth sounds from the B1on, B3n, etc. If you check out something like Call Me Ruin (new Gary Numan track), then the synth bass sound type from that is very doable. I am having to bass this off my own record collection, but something like Absolute by Scritti Politti is just about doable on the B3n, but you have to work for it, whereas on the Bass V-amp it's pretty easy. For a Yamaha DX7 bass sound, then in theory the PWM sounds on the Zoom B2 or B9 should be perfect, but the tracking is so terrible it's unplayable, and for pedals only the Korg will get you anywhere close, from memory, but only one of the effects types, which might well just be a filter (it's been a while since I had a G5), but you'd still be better off with a keyboard, so there are sounds on early Nine Inch Nails that would be hard to obtain. For the sub-bass sound a Boss OC2 or clone with the direct sound turned off is your best hope, as even the octaver on the B3n doesn't do the job there.
Edit: I gave my OC2 away to a friend as I wasn't using it much, but I got a clone again in the end. Maybe I should try harder to get an OC2 sound from the Zooms, but they are reasonable octavers, but don't have that OC2 synthiness. In a sense, the beauty of the OC2 is that it's not actually that good an octaver.