Visors are a classic but I'd really have to say implants have been a big thing for me recently. The invasiveness, the ways you can physically replace parts of someone's body with designs of your own creation, the way that mental implants weave themselves into a person's head and cannot be easily removed without damaging their brain entirely without medical intervention, the way they excise complete and utter control by electronically stimulating the brain until it's operating under acceptable parameters, it's the sheer guarantee of technology to do its work instead of having to simply rely on sensory stimuli to drop someone into trance

I've still been getting a good taste for things that can be done practically with respect to real hypno, and I've been growing more of an appreciation for other aspects of it as of late, but implants are insanely up there for me for that reason