As I worked in this industry both in other people companies and my own as well I would definitely stick with 3 major areas:

1. Word of mouth: people and companies in this business usually know each other, start with the smaller ones you can reach in your network, ask them for reference and testimonial, let them spread the info.

2. Promoted reviews and Linkedin influencers, again try starting with small/local/regional people/magazines in SaaS/Software area, offer them free trial.

3. Targeted campaigns and provocative comparison, usual cold mail selling will not get you there
(probably), so try target your potential customer base with smaller advertising campaigns, precisely focused.