Want tubeless? You need tubeless tape. Well, you don't *need* it but it makes everything a lot simpler, and this Schwalbe tape makes it about the simplest it can be. It's expensive, but it's really good.
Pros: Seals first time, handles high pressures, adhesive works well
If you're switching to tubeless you might baulk at the price of dedicated tubeless tape and try to get the job done with insulating tape, or duct tape, or whatever else you've got knocking about. It tends to work okay at lower pressures but if you're running a 28mm tubeless road tyre at 80psi then you'll often spring a leak, in my experience.
Schwalbe's tubeless tape is designed to handle high pressures, and does so extremely well. Assuming your rim bed is clean and dry it's super-easy to fit, with an adhesive that's stronger than some of the other options. Make sure you get the right width for a good seal: you want the tape to fill the whole of the rim bed. Generally you'll want tape that's a few millimetres wider than the stated internal width to account for the fact that the tape drops into the recessed middle section of the rim.