Tim Keller is NOT a mainliner. He is ordained in the PCA. I’ve attended his church a cohple time. Very impressed with what is happening there.
Aside from Tim Keller, D James Kennedy of Coral Ridge Presbyterian Church, RC Sproul of Ligonier Ministries a popular teacher-scholar and Phil Ryken, President of Wheaton College are all PCA ministers.
The late Francis Schaeffer of L’Abri is considered a foremost evangelical Christian thinker and a PCA minister.