HamUniverse used to exist and have a great link showing ideal lengths for end-fed random (non-resonant) wire antennas.
See all the explanation and evolution on the archived article, but these are the best lengths (in feet) that I always referenced:
29, 35.5, 41, 58, 71, 84, 107, 119, 148, 203, 347, 407, 423
The HamUniverse article is linked from the random wires page from AB3AP.