B2B partnerships vs cold outreach: which has worked better for you?

I've been spending more time looking at B2B partnerships lately, especially with agencies, consultants, IT providers, and other businesses that already have relationships with potential customers.

What I find interesting is that the hardest part isn't finding people who are willing to promote something. It's finding partners who actually have the right audience and a reason to recommend the product.

Cold outreach gives you more volume, but partnerships can potentially give you more trust.

For those who have experience with B2B partnerships:

What has worked better for you?

1. Direct cold outreach
2. Referral partnerships
3. Affiliate programs
4. Strategic partnerships

I'd be interested in hearing what actually produced results rather than what looked good on paper.