Listing agents: what do you do when referrals are not enough?

For agents who already get a decent amount of business from referrals, past clients, and sphere:

How do you generate more listing opportunities when that source is not enough?

I keep seeing agents mention cold calling, expireds, FSBOs, farming, open houses, paid leads, content, and becoming a local authority.

But I’m curious about the real experience behind those channels.

What have you tried to generate more seller/listing opportunities?

What worked, what disappointed you, and what felt like a waste of time or money?