Utilities
Some utilities are specific to a particular implementation.
The FinnAPL Idiom Library - vendor independent
General Utilities - vendor independent
Yale Idiom List (Perlis & Rugaber, 1977) - vendor independent
APL2 IDIOMS Library - Over 650 APL2 phrases for IBM's APL2 and compatible APLs (e.g. APL+Win, APLX, Visual APL)