Advice to find B2B beta-testers in tech-startups realm

So I launched my startup a few days ago to help startups offer expensive giveaways to their customers at 1/10th of the cost through our cost-sharing program. With these tempting giveaways, they can create that buzz, traffic and leads that companies like appsumo, zagg, teambuy.ca etc are able to generate.

Currently, I am employing the cold-email tactic. But surely, there is got to be a slightly less time consuming and more efficient method of reaching out to clusters of startups, no?

Any advice would be highly appreciated :)

Adeel V Founder, www.killergiveaways.com