I would start with the real estate broker side and just get in the door and ask them if you can help cold call for them (calling FSBO or other off market properties to see if they would list their home with the agency).

I’m looking to do a lot of ground work, cold calling expired homes and for sale by owners, running numbers, and making a lot of deals.

However, is cold calling Tax Delinquent leads an efficient use of one's time, or would you just send them direct mail? 

Is it because of the cold season and no one moving?

Fortunately, taking a few simple steps to winterize your pipes before the cold season begins can effectively ward off any cold-weather plumbing issues.Store Outdoor FurnitureOutdoor living spaces can be a major selling point for tenants.

I’ve never been around cold weather so it was never a thought about how well insulated it has to be to connect to the house.

Needs about 50k worth of work and still owes about 80-90k the comps in the area are going for $150k-$168 its a corner lot etc. i am very new very very new to wholesaling and this is one of the very first cold calls i made where the owner wanted to sell the issue is it not alot of room  fix and flip and most importantly get my fee so wanted to see of any other creative ways i can make things deal work for all parties involved.

Has anyone laid sod in cold weather?

Using things like direct mail, cold calling, door-knocking, bandit signs, advertising, etc. 

In my humble opinion these routes are much more refined ways to search than just randomly cold calling banks.