Obviously I am not only a terrific shill but potentially a vastly successful scam artist.
Hardly anyone ever hears the whoosh. 
Tesla. As a shill, I need one of their cars to show off.
Old El Paso.
I could probably die happy with all the free salsa, chips, dips and Mexican food and Mexican food accessories that I could consume.
I’d shill for anything I truly believe in: public access to knowledge, replacing trees, organic food, and great medical diagnostic devices or methods. That said, I’m a terrible introvert so it had better be an inside sales job.
Even though I’ve kind of moved away from them and feel that they charge a premium for little to no benefit (when it should be going towards ethical manufacturing, better customer service etc) I would still have to say Apple. I know how powerful that Reality Distortion Field is, and could very easily get sucked back in even without meaning to - to do it on purpose would be a piece of cake.
When I commuted I drove right past the Tesla plant. Tesla workers are awful drivers, and none of them drive Teslas. Just sayin’. Though maybe shills would.
Easy: Gibson Guitars/Musical Instruments. Taken private some years ago by Henry Juskiewicz, it has had an awful reputation for strategic planning choices (invested millions in a new electric guitar tech - fiber optic? - or just look up the Dusk Tiger or the Firebird X. Oy.) and is reputed to have a difficult working culture. The acoustic shop up in Montana has a better rep but most likely because it is far away from Nashville.
I would love to dive in, retrench the planning and improve the corporate culture. No reason it can’t be a maker of good tools, an iconic brand and a company that is admired.
Yeo’s Sweet Chilli Sauce.
I can’t live without it, firstly. Plus, I’ve already converted a dozen or more people, who also now cannot live without it.
In fact, I DO put that shit on everything! (If I was offered a lifetime supply, I would be saving some real coin, I think!)
Tabasco sauce.
Sturm, Ruger & Co. - good quality and a very broad product line. But this:
and Domino’s Pizza are close seconds. 