В чем разница между I for one think that- и I personally think that- ?Пожалуйста, приведите примеры.

To my understanding they both mean the same thing.

"I for one think that" kind of implies that you believe that the listener or many people do not think the same way as you. It implies that you are confident in your statement even though other people may not agree.
In my opinion it also implies that you are picking a side in an argument... If that makes sense?

On the other hand, "I personally think that" seems politer. It's more used when you are talking about something that you want to without there necessarily being an argument involved.

In reality they both mean the same thing. One just has slightly stronger implications. Don't worry it's very nuanced and contextual. Most times it's determined by how it's said. However, if you are reading it "I for one think" is stronger than "I personally think."

eg.
Mandy was adamant that the group go get noodles for dinner. Thomas was not so sure. It looked like they wouldn't end up eating out anywhere at this rate.
"I for one think that noodles sound great." said Marcus, fed up with all the fighting.

I personally think that ice cream is tastier than cake.