Die wenigsten Seiten bei den untersuchten Sprachen gibt es auf Griechisch.
I'm not able to identify the SVO in the sentence and also help me in identifying the case. (I see there is "gibt es" and also "auf").
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First, keep in mind that German is not an SVO language; word order is more flexible so you can't tell subject from object using position. Instead you get clues by knowing how words are inflected. Also, there are additional cases in German so you have to distinguish accusative objects from dative objects.
In this sentence, as noted in the other answer, the subject is "es". This is part of the phrase "es gibt" which translates to "there is/are" or "there exist(s)". Word for word it's "it gives" but that's not really what it means.
The accusative object is the entire phrase "die wenigsten Seiten bei den untersuchten Sprachen". You can tell this is a single grammatical unit because German require the verb ("gibt") be the second unit. Roughly it translates as "the fewest pages for the investigated languages". Note that even though it's an object it can come first in German. German usually puts the topic first, regardless of the grammatical role. The subject "es" doesn't qualify as a topic so it's placed after the verb.
As noted in the other answer, "auf Griechisch" means "in Greek". I'd call this a prepositional/adverbial phrase, not an object. (But you might consider "Griechisch" to be a prepositional object; it gets rather fuzzy sometimes.)
Putting it all together gives "There are the fewest pages for the investigated languages in Greek." This is a bit awkward in English and it flows better without the "there are" part: "The fewest pages for the investigated languages are in Greek."
It's helpful to remember that English and German versions of a sentence can have different grammar, and what may be a subject in one language might be an object in another language. You have to understand the sentence according to the rules of the language it's written in, and not rely too much on your experience with another language.