British Museum

Wireframe of new collections search

Finnish Museum

Finnish Museum: browse using facets

Freebase

Freebase: semantic search, dropdown options clarify search term, snippet description pull out is excellent

V & A

V&A: faceted search, advanced search, image & display methods - thumbnail / listing

National Maritime

National Maritime Museum: faceted search, lots of options to refine search, display methods

Rijksmuseum

Rijksmuseum search with sectional dropdown, combined full site search, faceted search