IK Multimedia frequently releases official preset packs from signature artists for all users (including those with the free CS version). These are usually found in the under "Manage My Products" > AmpliTube 5 > "Presets" tab.
(Note: The exact number varies slightly by AmpliTube version. Some older versions may have fewer presets; the latest free CS version includes ~40 if counting minor variants.) amplitube 5 presets list free