Yes, Studio One Artist and Pro come with native pre-loaded instruments (I don't know if they are actually VST instruments):
1. Mojito - analog style monosynth/bass synth
2. Mai Tai - analog style poly synth
3. Presence XT - Wavetable/Rompler/Sample Playback
4. Sample One XT - sampler/slicer
5. Impact XT - MPC-style drum sampler
They all have big libraries of presets, sounds, drum kits, etc.