hebrewbooks.com must be downloaded. I have an external disk called Otzros Hatorah. The searching facility is wonderful for Bar Ilan but not so good for the others. Otzar Hachochma is very expensive. I bought the Otzros Hatorah paying in $10 monthly installments. The Bar Ilan is a copy of seforim and not the original, so each commentary is separate but it has references. Sefaria has english ttanslation might have hashkafic questions. There is DBS which is similar to Bar Ilan but has no teshuvas. The Bar Ilan plus includes the Encylopedia Talmudis.
