What Jedi in canon reminded Light their entire career?

Mace dabbled with the darkside.

Mac created Vaapad which taps into emotions - specificlaly anger - to use during battle. it is riding the edge of the "darkside". At least two of his students (that I recall) who trained in this style feel completely to the darkside.

steamboat28 wrote: Plo Koon. Though, to be fair, he did invent the light-side equivalent of Force Lightning...

Please tell me you are not speaking of the lightning rod technique of his order.

It depends on what you consider canon. Here's a list off the top of my head:

Streen
Tionne
Kam Solusar
Anakin Solo
Corran Horn (aka Keiran Halcyon)
Leia Organa Solo

more I just looked up (but should have remembered) :dry: :

Dorsk 81
Kirana Ti
Cilghal
Ganner Rhysode
Tenel Ka
Lowbacca
Ben Skywalker

That's a surprisingly short list though, considering how many Jedi there are in the EU. I found that all the others I read about did have a brush with the dark side. Not a great track record, eh?