Keith Jarrett’s Standard Trio is one of the benchmarks for me.
Bill Evans trios with Scott LaFaro and post-LaFaro - another benchmark
Other great trios:
Shai Maestro
Bill Charlap
Tord Gustavsen
Carla Bley
Marcin Wasilewski
Brad Mehldau
Some more modern jazz piano trios
Since discovering Christian Pabst several years ago, I've been slowly expanding my catalog of good contemporary jazz piano trios. Among these include the absolutely fantastic Triosence and the equally melodious Yuko Mabuchi Trio. An older artist still putting out immaculately played and recorded albums is Steve Kuhn and his trio.
Any other suggestions?