The best way to boycott them is disconnect your cable or satellite from your television.
Odds are you'll still watch too much boob tube I know I do but I disconnected 9 years ago and loaded up my browsers with Ghostery and Ublock. No ads anywhere I go and I can block any content on any site I want permanently.
It's too difficult to boycott every business/corporation guilty or accused but removing their ads from your life is a good start granted you'll find yourself detached from a lot of friends and family completely integrated into the matrix. I avoid major brands, no fast food, no junk food and if I'm going to buy crap from China since there's little choice I'll buy it DIRECTLY from China on Ebay and Ali Express rather than Walmart, Amazon etc. who increase the selling price by a factor of 5 to 10. I used to look at the label on everything to find products made in the USA but it ultimately became pointless and a luxury for people with money to burn if you're going to buy strictly USA.
99.999% of us cannot afford to buy made in the USA and still have a roof over our heads.
So a boycott list?
Not a realistic idea tbh but changing your lifestyle on the other hand that's a similar move and the right direction. You can cut these people out of your life as much as possible and speaking of people?
I've boycotted celebrities both Hollywood AND internet.
Youtube and various social media celebrities are in many ways even worse than Hollywood's since Google/tube is a monopoly.
Ask someone like PewdiePie, a no talent idiot I've yet to talk to anyone who finds funny, how much does he spend on ADVERTISING every month?
I've asked countless big youtubers the answer is always, ALWAYS $0.00
Imagine even a legend rock band like The Rolling Stones releasing a new album but not spending any money to advertise it.
It would be a huge failure so consider these youtubers and other social media celebrities are being HAND SELECTED by google, Facecrook etc. and then actually believe they are successful on their own merits.
So as I said it's in many ways even more corrupt and rigged than the Hollywood celebrity system.