when pixel art is in question Photoshop is norm, and some time ago an pipeline to Zbrush (GoZ) could broadened the main ps artwork with 3d scenes, and/or additional sketching painting texturing with the PaintStop plugin [1][1][1] ~ [2][2] practically an advanced illustrating workflow but first You’ll need to get some knowhow in aPS and then dive in pZBR (now mZBR)
vector art is something completely different thing mostly coz the process of illustrating is more rigid but necessary for the output, and from my experience more intuitive forkflow has Inkscape [3] while Illustrator or Corel are more like master them till bone before trying to loose Your creativity!
recently I was playing with 3d vectors too [3] so in essence combos from different programs can bring You to that moment of great results!, altho it takes time to master some app but usually the same process will choke up Your creativity tho what can be cushioned somehow [4] and thats why exist collaboration between concepts artists and skilled craftsmen so would be achieved greatest results, so per’se software that brings great results dont means is greatest 