Which type of anchor comes in the largest diameter?

Toggle bolts are recognized for having the largest diameter among the options provided. This is due to their design, which typically includes a metal toggle mechanism that expands behind the wall when inserted, allowing for a secure hold. The size and strength of toggle bolts make them particularly suitable for heavy loads in hollow walls, like drywall or plaster. Their ability to distribute weight over a larger area ensures that they can handle substantial weight without failing, which is not as easily achieved with the other types of anchors listed.

Plastic anchors are generally smaller and suitable for lightweight applications. Snap-type toggles, while also robust, are often not as large in diameter as traditional toggle bolts. Self-drilling screws are versatile and easy to use but do not typically match the diameter of toggle bolts, as they are primarily designed for anchoring directly into solid materials without the need for a wall cavity.