ACE is a chess engine still in development. It has a lot of pruning:
-Alpha-Beta pruning -Null-move pruning, with R >= 3 -Futility pruning, with a margin of 350cp -Extended futility pruning, with a margin of 550cp -Limited razoring, reduces the search depth by 1 ply, margin of 920cp -Late move reduction, for the later half of the moves at root -Delta pruning, with a margin of 250cp
It has 2 killer slots/ply, and history heuristic as well, to speed up move ordering.
Bugs: The transposition table (still in development) doesn't work The displayed PV line is incorrect, since I started implementing the transposition table