Apollo, LeadMagic, and Findymail is a solid starting combo, but you're missing some key pieces that most people run in their waterfalls now.
Apollo is great for the initial pass - decent coverage and you're probably already paying for it. LeadMagic has been getting better coverage lately and their verification is solid. Findymail is reliable but can get expensive fast on volume.
Most waterfalls I see now include ZoomInfo (if budget allows), Prospeo for the verification layer, and either Hunter or Snov.io as backup enrichers. The pattern is usually Apollo → ZoomInfo → LeadMagic → Findymail → Hunter, with Prospeo verification at the end.
Hunter still finds emails others miss, especially for smaller companies. Snov.io is cheaper than Findymail for volume but slightly lower quality. If you're doing any international prospecting, definitely add Kaspr - they crush it on European contacts.
The real trick is setting up proper conditional logic so you're not burning credits on contacts that already have verified emails from earlier providers. Also consider Clearout or ZeroBounce for a final deliverability check if you're sending high volume.
Your three-provider setup will work fine for getting started, but plan to expand as you scale. Most teams end up with 4-5 enrichment providers plus 1-2 verification tools to hit 85%+ coverage on good lists.