A repertory is an index to the Materia Medica: you look up a symptom and it lists the remedies recorded under it, each weighted by how well the observation was confirmed. It narrows a case to a handful of remedies worth reading about properly. It does not choose one — a repertorisation is an index, not a prescription.
Two classical repertories are reproduced here, chapter by chapter, free and without an account.
These pages are for reading. To search all 71,457 rubrics at once, build an analysis from several rubrics and see the remedies ranked by grade sum, you need a free account.