Is there a website that lists CFOs of tech companies or digital agencies that also includes their emails?

There are 2 best business email lists provider company.
- InfoUSA
-EmailDatas [https://www.emaildatas.com/]
These customers gave consent about receiving emails and are most likely the ones that earned your trust already. Buy a targeted business email list that emphasizes clients who are receptive to your offers. This will generate more than 90% accurate business leads.

If you are looking for basic database, there are "n" number of sources. But what you may need is a customised database based on your key parameters as mentioned by you. For this, you should consider a consultant/company who can build customise list.
I can help you as I have huge database at disposal and all information are updated (email also).
Let me know if you need it.

Her are a few options that might help:
https://discoverorg.com/
www.lead411.com

If I were in your shoes (assuming you have a little bit of budget), I would pull together a list of target companies. This can be done pretty easily, as their are many public databases of companies you can scrape (eg. Inc 5000).

Then I would have a low cost freelancer from Upwork find the CFO or finance decision maker for each company. You'll pay around $3-5 per hour for this kind work, and a freelancer can usually find around 30 leads per hour. It's a very cost effective method.

Here are the steps to grabbing anyone's email off Linkedin:

1. Install Chrome browser https://www.google.com/chrome/
2. Install Email Hunter extension https://emailhunter.co/chrome
3. Head to Linkedin.com and search for CFO
4. Next to the connect button on their profile, you will see a new button with a target icon, click that.
5. Their email should appear most of the time. Sometimes you have to type in the URL of the company they are with now.

Note: You will rarely receive a positive response from anyone after a cold email. Hopefully what you are offering in return for opening your email (valuable proposition or opportunity) is enough for them to want to reply. I would begin the email in an apologetic fashion regardless;
"Hello _____,

I would first like to apologize for the cold email. I myself hate receiving them, but I found your experience to be an exact fit for _____ so I had to reach out via email...."

Enjoy :)

There are 2 information list brokers that come to mind.
https://www.infousa.com/product/business-lists/
https://www.salesgenie.com/

Both of these sites have extensive demographic data to target the information you are seeking.

Remember if you are bulk emailing these people you will be in violation of multiple countries SPAM laws. If you email each one individually and type it manually tailored to each companies CFO it will not violate those laws as you sent each one manually.