6 of the most ridiculously large synth workstation plugins that can handle every part of a track: "This powerhouse of a synth has all of the sounds you need"

Spectrasonics Omnisphere 2 Plugin.

Synth workstations like the classic Korg Triton offer a complete production suite in a single unit; synths, samples, effects, sequencing and arrangement capabilities all coming together to create a one-stop shop for track-building. 

These aren't only found in hardware form, though, and if you're looking to save on studio space, there are plenty of synth workstation plugins on the market that provide all the music-making power one could ask for in a single software package.