Illuminated reticles, red dots, etc. are legal. Projecting a beam onto the target is not legal for deer & elk; presumably it is legal for everything else.
See WAC 232-12-045
Hunting equipment restrictions.
(1) It is unlawful to hunt deer or elk with the aid of infrared night vision equipment or with laser sights (not to include range finders) capable of projecting a beam onto the target, while in possession or control of a firearm, bow and arrow, or crossbow.
(2) It is unlawful to use radio-telemetry equipment to locate and hunt wildlife with transmitters attached to them.