Skill Borrower, Soulbright Flamekin, and Deck manipulation.
You can activate it three more times; those will count as “new activations” and you will get the bonus effect.
If the top card of the library changes or ceases to be revealed for any period of time before being revealed again, it's considered a brand new object. In particular, Skill Borrower will have a brand new ability that had nothing to do with the previous ability it had. This new ability doesn't share memory with the old one, so the number of times the ability has been activated is effectively reset.
With Sensei's Divining Top, the top card never ceases to be revealed, so all players get to know if it changes to another card or not (in practice, this particular situation might require that the top card is left clearly separated while the player is choosing how to reorder the cards). If the same card is left on top, Skill Borrower has the same ability; otherwise, it has a new ability.
Daniel Kitachewsky
L3, Paris, France
Rules NetRep