1. Also 'collectable', an adjective meaning any item capable of being collected. Could be anything regardless of value and rarity, like plastic frogs, matchboxes or bottle caps, also as in technically possibly to collect.
2. noun - an object suitable for a collection, originally a work of fine art or an antique, now including also any of a wide variety of items collected as a hobby, for display, or as an investment whose value may appreciate.
An asset of limited supply that is sought for a variety of reasons including, it is hoped, an increase in value. Stamps, antiques, coins, and works of art are among the many things usually classified as collectibles. Collectibles are often regarded by investors as hedges against inflation, since their value tends to appreciate most when general prices are rising. The collectibles market represents a very tricky investment for inexperienced investors.
Collectible as noun I think should be translated as "worth collecting" which could involve 'hand made' or with some kind of special quality which makes them both attractive, both limited in quantity but still somehow available, and that they can not be reproduced in quantity without any effort at all.
Any 'collectible' does not need to be signed by an individuall artist to be worth collecting but the quality in its widest sense should be apparent, unique and not easily copied.
One warning sign is that if something is advertised as manufactured specifically to be a "collectible", it is very likely to be worthless as soon as the advertising stops and overpriced at the time of purchase which defeats its purpose of being an investent.