Depending how you are using the Helix, you'll want a different amps and speakers. You can run Helix through a conventional amp and cabinet, through an amp and cabinet that is biased to guitar tones, or through a simple FRFR amp and speaker.
In my case, for live stage use, I want to hear what exactly what the audience hears from the main PA speakers which are FRFR. So I monitor myself with a simple FRFR powered speaker. I shopped around and found the Mackie Thump12 to have a decent FRFR sound at a volume that's loud enough to hear over the other band members, has a decent price and is easy to carry in one hand.
Since it is impossible for most of the audience to hear a stereo image from the main PA speakers, I run everything mono, including the use of just one speaker for me.
While I miss the sound and feel of a cranked tube amp and cabinet behind me, with my FRFR speaker I have much better control over what I am sending to the main PA and the ability to adjust my stage level without affecting the main mix. Also, when I switch among Marshall, Fender, and Vox amp and cabinet models, I feel I am getting the maximum benefit of these different models without being limited by the physical amp and speaker.