5 Underrated Cold Email Tools Your Agency Should Try in 2025

If you run an agency, you know cold email involves a lot of moving parts: writing sequences that don’t sound like templates, managing sender reputation across multiple domains, tracking who actually responds (and why), personalizing at scale without losing your mind, and constantly testing what works. The right cold email tools can make these tasks a whole lot easier.

However, finding cold email tools that actually deliver results is easier said than done. We’re spoiled for choice, but still (or maybe because of it), most agencies default to the same handful of popular platforms everyone talks about on LinkedIn. The problem? What’s popular isn’t always what works best for your specific agency challenges.

What if we told you that there are some great, albeit lesser-known, tools that solve specific agency problems better than the mainstream options? If you’re interested in learning what these platforms are but don’t have the time to do the research, we’re here to help.

This article focuses on five underrated cold email tools built for agencies dealing with real-world constraints: tight budgets, multiple client accounts, and the constant pressure to prove ROI.

1.   Instantly

Instantly is the cold email software agencies turn to when they need campaigns running yesterday. It handles the technical side of deliverability and sender reputation while you focus on writing copy that actually converts.

The AI-powered warmup feature is the most talked-about part of Instantly, and for good reason. Your domains are campaign-ready in days instead of the typical 3-4 week manual warmup period. Agencies will find this particularly valuable when launching campaigns for multiple clients on tight deadlines.

Beyond warmup, Instantly bundles tools that would normally require separate subscriptions. The platform includes a 450 million contact database for prospecting, a built-in email verifier to protect deliverability, and an AI writer that uses data points from your lead lists (name, company, job title) to craft personalized intro lines for each recipient.

As your outreach grows, Instantly scales with you through tiered pricing that expands your capacity well…instantly. You can upgrade tiers without rebuilding campaigns or migrating data. The unlimited email accounts feature means you can run campaigns across different client brands or test various sender personas without hitting account limits or paying per-seat fees.

The analytics dashboard feeds directly into A/B testing, so tweaking subject lines or call-to-action copy happens in real time. Instantly’s API library keeps expanding too, which means connecting it to your existing CRM, lead enrichment tools, or reporting dashboards stays simple.

Pricing: If growth is on your radar (and you’re researching cold email platforms, so it probably is), Instantly deserves a close look. Plans start at $37 monthly, with the Hypergrowth tier at $97 monthly covering most agency workflows.

2.   GMass

GMass is one of the simplest and smartest cold email tools for agencies that work inside Gmail. Think of it as Gmail 2.0—it looks and feels familiar (so onboarding your team takes minutes), but handles outreach infinitely better.

GMass is first and foremost a tool for sending personalized cold emails at scale. It might not have the fancy standalone dashboards that other platforms offer, but what it does, it does exceptionally well. It also integrates directly with Google Sheets for list management, so you can update campaigns on the fly without importing and exporting files.

You can send automated sequences and track opens, just as you would with any cold email platform. You can schedule campaigns based on recipient time zones, automate follow-ups without sounding robotic, and run A/B tests to refine your messaging. The campaign builder operates right inside Gmail, so your team doesn’t need to learn a new interface or abandon their workflow.

Pricing: GMass pricing starts at just $18/month, scaling up to $27/month for premium features.

3.   QuickMail

Not only will QuickMail help you scale campaigns across multiple inboxes without damaging your sender reputation, but it’s also built specifically for agencies that need serious control over their outreach infrastructure.

QuickMail pioneered inbox rotation back in 2014, a feature now considered essential for high-volume cold email. Instead of manually managing separate campaigns, QuickMail rotates sending across your inbox pool with a single click, keeping each account under safe daily limits while your total volume scales.

There’s also detailed send-day attribution analytics to track who actually opened your cold emails based on when emails were delivered, not just when they were opened. QuickMail’s dashboard shows exactly which messages convert and which fall flat.

Pricing: Pricing starts at $49/month for agencies managing multiple client accounts.

4.   EmailChaser

Despite flying under the radar, EmailChaser is built as a genuinely all-in-one platform. As such, it doesn’t ask you to subscribe to five different platforms to run campaigns but bundles everything under one roof: campaign management, a sales CRM, email finder, and email verifier. All the essentials agencies need without the subscription sprawl.

In the platform itself, you’ll see inbox rotation handled automatically (spreading sends across unlimited email accounts), gradual volume ramp-up (starting at 5 emails per day in week one, building to 40 by week eight), and double-verification built right in (keeping bounce rates under 1%). Along with this, the tool uses ChatGPT to generate email variations instead of spintax, so every recipient gets a genuinely unique message.

With this setup in place, you can launch campaigns knowing your deliverability is protected. EmailChaser deliberately skips the warmup feature (the founder argues it’s counterproductive), focusing instead on proper technical setup and gradual sending increases. All campaigns run from your actual Gmail or Outlook servers, not third-party infrastructure.

Pricing: Pricing starts at $37/month. The professional plan costs $97/month and includes unlimited email accounts.

5.   Snov.io

It’d be remiss of us not to mention the tool that agencies use when they need prospecting and outreach in one place: Snov.io. Even Snov.io’s starter plan at $30/month is great for most lead generation tasks agencies face daily. Teams use it to find verified email addresses, scrape LinkedIn for prospects, and launch automated sequences without switching platforms.

The platform sends personalized cold emails at scale while also handling the prospecting work upfront. You can build logic-based sequences (if a prospect opens but doesn’t reply, send X; if they click a link, send Y), which gives you more control than basic follow-up automation.

Snov.io also integrates directly with LinkedIn, letting you extract leads with email addresses right from profiles and Sales Navigator. The Chrome extension makes prospecting feel less like data entry and more like actual relationship building. For agencies managing both prospecting and outreach, it eliminates the need for tools like Apollo or ZoomInfo stacked on top of your email platform.

Final Thoughts

The right cold email tool can change how your agency gets leads, but don’t rush the decision. Make sure it actually works for your team first. Most tools on this list offer free trials or cheap starter plans, so use them to test whether the platform does what you need before committing long-term.

• Focus on your biggest problems: Are emails landing in spam? Is prospecting eating up too much time? Do you need better client management?
• The basics matter most: deliverability, email verification, and inbox rotation beat fancy AI features every time.

If you want the most reliable option with the best track record, Instantly is still the top choice. Agencies consistently report the highest inbox placement rates and the smoothest onboarding experience. Ready to see the difference? Start your free trial today and run your first campaign within minutes.