Tower of Infinite Evil has some 2E Combat & Tactics Inspired Weapon Properties for 5E
Another iteration of the Sly Flourish Single Use Magic Item Generator.
My own stab at porting Numenera's GM Intrusions over to 5E
Donjon has some 5E specific generators, but the best one is the Trinket generator.
Sly Flourish has a generator that gives a list of Numenera style single use magic items.