Over the years, the band has rehearsed many songs that were not played on the subsequent tour. Here's a list of songs that we know were rehearsed but not played. 2001
Carousel - Rehearsed for the Headlining European Tour in 2001. The song was likely performed pre-Linkin Park (Xero/Hybrid Theory Era)
2003
Breaking The Habit - Rehearsed for the beginning of the Meteora Tour (early 2003), but not performed until the end of the year.
Forgotten - Rehearsed for the Meteora World Tour but was never played.
2007
The Little Things Give You Away - Was rehearsed for the MTM Promo Tour but wasn't played until the European Tour.
2008
No Roads Left - Rehearsed for the European and Projekt Revolution 2008 Tours, but not played due to the band thinking it didn't sound good enough live. Dropped from Euro Set X just before the first show.
2009
By Myself - A reliable source said the band rehearsed this song in June 2009.
2010
Points Of Authority - Was on one of the London 2010 sets and the soundcheck set, but was wound up being replaced with No More Sorrow. (Not necessarily rehearsed)
Somewhere I Belong - Was on one of the London 2010 sets, but was wound up being replaced with No More Sorrow. (Not necessarily rehearsed)
2012
I'LL BE GONE - Chester said in an LPU Chat in December 2012 they rehearsed IBG, but didn't play it on the following tour.
Leave Out All The Rest - The song was on a potential rehearsal set at the Cape Town summit in 2012, but ended up being performed as the Ballad Medley instead.
Wretches and Kings - Pooch mentioned that the band was rehearsing this song for the Honda Civic Tour.
2014
A Light That Never Comes - The full version of the song was rehearsed for the Carnivores Tour in 2014, but ultimately not played.
A Line In The Sand - The band performed all of The Hunting Party at some point before touring for it.
A Place For My Head - The song was rehearsed for the Carnivores Tour in 2014, but not played regularly. It was performed during the soundcheck during the Amsterdam Summit, but didn't appear in a setlist until the new Set A debuted in 2015.
All For Nothing - The band performed all of The Hunting Party at some point before touring for it.
Breaking The Habit - The song was rehearsed for the Carnivores Tour in 2014, but ultimately not played.
By Myself - The song was rehearsed for the Carnivores Tour in 2014, but ultimately not played. It was only performed at the Download Festival celebrating Hybrid Theory's 14th Anniversary.
Cure For The Itch - The song was rehearsed for the Carnivores Tour in 2014, but ultimately not played. It was only performed at the Download Festival celebrating Hybrid Theory's 14th Anniversary.
Final Masquerade - The band performed all of The Hunting Party at some point before touring for it. The song debuted later on the tour, during the Carnivores Tour.
Forgotten - The song was rehearsed for the Carnivores Tour in 2014, but ultimately not played. It was only performed at the Download Festival celebrating Hybrid Theory's 14th Anniversary.
Keys To The Kingdom - The band performed all of The Hunting Party at some point before touring for it.
Mark The Graves - The band performed all of The Hunting Party at some point before touring for it.
No More Sorrow - The song was rehearsed for the Carnivores Tour in 2014, but ultimately not played.
Pushing Me Away - The song was rehearsed for the Carnivores Tour in 2014, but ultimately not played. It was only performed at the Download Festival celebrating Hybrid Theory's 14th Anniversary.
Rebellion - The band performed all of The Hunting Party at some point before touring for it. The song debuted later on the tour, during the Carnivores Tour.
War - The band performed all of The Hunting Party at some point before touring for it.
When They Come For Me - The song was rehearsed for the Carnivores Tour in 2014, but ultimately not played.
Wretches and Kings - The song was rehearsed for the Carnivores Tour in 2014, but ultimately not played.
2015
War - Based on an Instagram post, the band seemed to have been rehearsing War for The Hunting Party North American Tour, but it didn't make it into the setlist. Instead, From The Inside and A Place For My Head were performed.
Anyone have anything else to add?