Show and hide layers in the Timeline panel

You can mark a layer as shy and then use the Hide Shy Layers composition switch at the top of the Timeline panel to hide all shy layers in the Timeline panel layer outline. Making layers shy is useful for making room in the Timeline panel to show the layers and layer properties that you want to adjust.

The icon in the Switches column indicates whether a layer is shy  or not shy .

Shy layers are still rendered, both for previews and for final output. To exclude layers from previews or final output, use the Video switch or make the layer a guide layer.

You can also filter layers in the Timeline panel to show only layers with properties that match a search string or certain other characteristics. See Search and filter in the Timeline, Project, and Effects & Presets panels and Showing properties and groups in the Timeline panel.

Lloyd Alvarez provides a script on his After Effects Scripts website with which you can tag layers and then select, shy, and solo layers according to their tags. The tags are appended to comments in the Comments field in the Timeline panel.