La Tène curves, horse gear, and enamelled bronze.
Iron Age 'Celtic' art favours flowing asymmetric curves — trumpet voids, triskeles, stylised birds — quite unlike Roman symmetry. Common metal finds include horse gear (terrets/rein rings, bridle bits, strap unions), brooches of La Tène construction, and red glass 'enamel' inlays glowing in cast bronze cells.
Coins aside, look for the champlevé red inlay, the confident compass-drawn curve, and cast loops with wear from straps. Iron survives less kindly — currency bars, sword blades in scabbards, and tools come rusted but recognisable in profile.
This material can be spectacular and is often regionally significant; record findspots precisely and consider formal reporting even where not required. Describe motifs concretely (triskele, trumpet scroll), note inlay colours, and weigh cast pieces — completeness of a horse-gear set matters to interpretation.
Recognising Bronze Age metalwork
Recognising Roman military fittings
Recognising Anglo-Saxon metalwork
Recognising Viking and Norse finds