A preset is a saved filter you can apply with one click. Presets are scoped to one tab; a server preset is not visible on the Processes tab.

A preset name on a toolbar button doubles as a toggle: click to apply, click again to remove. You can have several toolbar presets toggled on at the same time; their conditions combine with the active condition tree using the same single AND / OR logical operator.
Open the filter builder, set up the conditions you want, then click Save as.... A small input dialog asks for:
Save also applies the preset to the current tab. To make the preset appear on the toolbar, set the Show as button flag later from the preset's Edit dialog or from Manage presets.

Open Manage presets from the presets menu. The Manage filter presets dialog opens with the list of presets for the current tab. From there you can:
A preview pane below the list shows the selected preset as a stack of chips so you can see what conditions it carries without opening the builder.
The presets menu has an Advanced submenu with Export presets and Import presets commands. Export writes every preset for the current tab to a single JSON file. Import reads the same format back in and asks how to handle duplicates:
Either way, brand-new presets are appended at the end of the list. After the import a small dialog summarizes how many were imported, replaced, skipped, or errored.
Use export to back up your presets or share them with another machine; import to restore them.
Reset to defaults is the last item in the Advanced submenu. It opens a task dialog with three choices:
Back custom presets up with export first if you plan to use Remove all.
Presets are stored in the program's SQLite settings database. They survive program restarts and are scoped per tab type (process, session, server). Three separate lists exist, one per tab.