A target list is a short list of named businesses in your segments and service area, each with a written reason it would need notary work. The reason is what separates a target list from a phone book. Good reasons are events that create documents someone has to sign in front of a notary.
Example: a title agency opens a second office across the county line. Example: a senior living operator opens a new community in your area, and some new residents will need powers of attorney notarized. Example: a company agrees to buy another, and some of the deal documents need a notary. Example: an employer starts hiring in states where it has no office. Completing Form I-9 as its authorized representative is not a notarization, but where your state allows it, it can still be work you sell; ask first how the employer handles remote hires, because employers enrolled in E-Verify in good standing can examine documents remotely instead.
For each business, record the segment, the reason, where you saw it and when, the person who decides, and how you could reach them. If you do not know something, write unknown. A guess in the decider column costs more than a blank, because it sends your first message to the wrong person with the wrong pitch.
Leave out businesses you already serve, and keep the list small enough to research by hand. Contact databases and list vendors will sell you long lists of names sorted by industry code, but a name with no reason gets a generic pitch, and office managers delete generic pitches. The buyer signals guide explains which events are worth writing down.