1. You can try cold emailing the cofounders or department chiefs (CTO, VP of Growth, etc.) of small to mid-size companies with a product that requires dev work.
For example, you can try targeting startups who just raised a recent round (= more aggressive growth goals) to pick up some dev/engineering slack on a project basis as they scale quickly.
There are tons of email finders (hunter.io, voilanorbert.com) that let you enter someone's full name and company name to find their email or their company's email format.
2. Keep your cold email short and frame hiring you as a way to launch and scale experiments, product test features, etc. on a project basis without needing to hire an additional full-time employee .
3. Briefly provide 2 examples of how you used your engineering skills to achieve an important business goal or solve a problem for companies you've worked for. Provide 1-2 reference quotes vouching for your work and reliability with links to their Linkedin profiles.
4. Offer to work on a project basis and offer to start on a small project with a defined deliverable to show them what you can achieve and how you'd be like working for you.
5. A/B test different email approaches. For example, you can also try asking the prospect "What are your top 3 roadblocks that require dev work? I can provide you insights on the most time efficient solutions that take up less people resources" to open the conversation and demonstrate your expertise.
6. Ask your current and previous colleagues to leave testimonials on your Linkedin profile to further show you're legit and skilled.