Where can I get the original title of books, i.e. Marquez's book "100 Years of Solitude" has the original title "Cien Años de Soledad".
Some of the Hungarian publisher list this info, but especially in English language countries, book stores not do it.
The Deutsche Nationalbibliothek (DNB) has the original titles together with the German titles, see e.g.
https://portal.dnb.de/opac.htm?method=showFullRecord¤tResultId=%22\%22Hundert%22+and+%22Jahre%22+and+%22Einsamkeit\%22%22%26any¤tPosition=9
Titel/Bezeichnung Hundert Jahre Einsamkeit : Roman / Gabriel García Márquez. Aus dem Span. von Curt Meyer-Clason
Einheitssachtitel Cien años de soledad <dt.>
You can get Data from them via https://portal.dnb.de/metadataShop.htm (all in German; some data sets you must buy, some are free).
(no, this doesn't full answer the question, but it's hopefully something to guide you in the right direction, and it's too long for a comment)
What you'd likely need to find is sometimes called a 'FRBRized catalog'. FRBR is the "Functional Requirements for Bibliographic Records", which is a reference model for bibliographic catalogs.
To summarize -- an old library 'card catalog' typically groups all books of a given story ("Creative Work" in FRBR) into one card, possibly with a note that a translation is available. Modern card catalogs and bookstores tend to be indexed by ISBN number, so every different printing of a book ("Manifestation" in FRBR) shows up as a different record.
What you'd need to find is either something that links multiple Manifestations back to the higher Work concept, or that links Expressions (the words used to tell the story, which links Works to Manifestations) via a Translation relationship.
A few other acronyms that might help you in searching -- RDA (Resource Description & Access, a cataloging standard), OCLC (Online Computer Library Center, a cooperative for library cataloging), WEMI (Work Expression Manifestation Item, shorthand for talking about the FRBR Group 1 Entities).
