Well a potion that you drink that makes you 20th level (yeah I don't think you'll give me that
More reasonably, probably a magical ring (Jump, sustenance, +1 anything
Boots of el... gnomish kind?
As for mundane things, perhaps a tea/party set for gnomes and halflings, book of feats from gnome adventurers, perhaps a spellbook/diary from an illusionist (not that it would have anything he could use
Since starting with no equipment at all, a good instrument (He plays the violin
Carving tools (Craft figurines