Good to hear from you! We also enjoyed working with Triplebyte, and still think that hiring/recruiting is a great use of EthicalAds.
In general we've also found success with higher LTV SaaS products, and you might expect for display ads. Digital Ocean, Twilio, and MongoDB are folks who have done big campaigns with us over the years, as an example. I have a sort spot for the folks at Twilio, because they were actually the ones who convinced us to do ads on Read the Docs originally, with a hacked together campaign way back in like 2015 :) Running a Python-targeted campaign, with Python code in the ad image, linking to a Python-specific landing page tutorial really showed the vision for what we could build.
We've also had a lot of luck with more niche targeting for specific audiences. Our current major audiences are Backend, Frontend, Data Science, Security, & Devops: https://www.ethicalads.io/advertisers/#audiences -- Each of these audiences has had good success with folks targeting specific products (Think feature flagging in JS for frontend devs, and ML model services for data science).
As we grow and optimize our ML modeling, we're going to continue to expand our high-level topics, as well as offer more finer grained targeting.