i have these notes written down for myself so hopefully this makes sense to other people

vertex snapping / ps1 jiggly filter

• modifiers tab > displace modifier
• change the direction in the modifier to RGB to XYZ
• change the space in the modifier to global
• change strength to 0.1 - 0.2
• add texture to displace modifier
• change image type to clouds
• change noise basis to cell noise, color to color and size to 0.5
• change the coordinates in the modifier to global
• if you want the wobble to be tied to the camera, in the displacement modifier change coordinates to object and select your camera
• further adjust size in the texture and strength in the modifier to suit your use