Assuming God is absolutely good to the furthest extreme possible and there are no other worlds out there like ours (with torah observant creatures), if so, why did He create finite number of worlds to bestow this good to? Surely, He is capable of creating other worlds like ours whereby some at least will have peoples who are willing to accept His torah. On the other hand, would this prove that there must be other worlds out there like ours with creatures like us who received His torah?
The basic answer to your question is that this is a hypothetical discussion and we cannot (at this point in time) know the answer as I will explain below. While we can say that Hashem's infinite goodness could lead him to create other worlds to bestow it on, we could also say that this good could require that any particular set of beings must be unique. Thus, once one set of beings (or universe) has been created, then that would be sufficient to receive the infinite good that Hashem bestows. It appears that Hashem specifically does not want us to know for sure because that would actually not be good for us.
It appears to me that knowledge for sure would harm us just like Hashem allows for doubt even though we know that He exists and gave us the Torah. I am saying that I can come up with circumstances in which the good would be each possibility. Personally I think there probably are others, but say that it is intrinsically unprovable.
I remember reading that by definition a created being must be finite in nature in order to exist. There cannot be two infinite beings. Additionally, for Hashem to bestow good upon the creation, that creation must lack something so that Hashem can bestow it on them. Only a finite being could lack something to begin with.
If you are asking about a finite number of worlds being created, we do not know how many worlds with intelligent life have been created because the Torah only speaks about this world. Note that the Torah does not speak about nations that do not deal with Bnai Yisael even though they exist. Similarly, it would not need to speak about other worlds as they would not be relevant to what we are being taught.
While Hashem could create other worlds, there is no way of proving the matter one way or the other. If Hashem has set up the universe to allow interstellar travel, then we might eventually find out. If He has set up the universe not to allow such travel, then we might never find out.
@mevaqesh reads your question as asking about an infinite number of such worlds as opposed to any finite number of such that may be. Indeed, this particular point could be addressed as a theoretical question. Isaac Asimov in one of his novels uses the concept of two is an impossible number. Thus, there could be an infinite number of finite universes or an infinite number of worlds within our universe (which would make it infinite is size though still finite as a creation) without changing the analysis of the question.
However the point that I was making was that the torah would not in any case address that question as it is referring only to this world and to those nations in this world that deal with the Bnai Yisrael. The fact that there may (or may not) be other worlds (or other universes) would not apply.
Thus, the entire point is that while Hashem can create in any of these modes, it appears that it is best for us not to know for sure.
Hashem providing infinite good can be taken to mean that He would therefore create as many beings as would fit into the universe(s), but as far as any individual group of beings would be concerned, that good would be provided to that group (like humans) alone.
If it is best for beings (like humans) to get in contact with others who have free will, then Hashem would have arranged it (although apparently in the future -maybe after mashiach comes). It is quite possible that at our level of development it would not be a good idea to meet others who may have passed the test that Adam Harishon failed, or may be at a different level in their development.
The Existence of Other Worlds By Baruch Crowley speaks of the ideas of other worlds and that aliens on UFOs (if they exist) may be in the realm of non-free willed beings like the nachash is said to have been before the aitz hada'as.
Chabad Is There Life on Other Planets? has the viewpoint
Dr. Velvl Greene was a microbiologist who was enlisted by NASA in their project to determine if there is life on Mars. He asked the Lubavitcher Rebbe privately if this was something he should be doing.
The Rebbe replied, “Dr. Greene, look for life on Mars! And if you don’t find it there, look somewhere else in the universe for it. Because for you to sit here and say there is no life outside of planet Earth is to put limitations on the Creator, and that is not something any of His creatures can do!”9
Several Torah scholars of past generations have discussed the possibility of life on other planets. Rabbi Chasdai Crescas (Spain, 1340–1411) wrote that there is nothing anywhere in Torah that negates such a possibility.3 Rabbi Yosef Albo (Spain, 1380–1444), on the other hand, disagreed.4 Rabbi Pinchas Horowitz (Poland 1765-1861), cites Albo, but rejects his thesis.5
3. Ohr Hashem 4:5.
4. Sefer Ha'Ikrim.
5. Sefer HaBrit HaShalem 1:3, 4.
Your question has many assumptions, some of which are accurate and some of which are not. Looking at each assumption may help.
You open by saying that G-d is absolutely good to the furthest extreme possible. This is an accurate, traditional belief like is found in the language of the Shemonah Esreh blessing for the year where it says, "because You are G-d, good and who does good..."
כי אל טוב ומטיב אתה
The next assumption, "there are no other worlds out there like ours (with torah observant creatures)", is according to a large segment of traditional Judaism not accurate. The concept that there are worlds like ours, meaning similar to ours is one of the foundations of Jewish belief. This idea is expressed in the text recited on Shabbat evening just before the Barchu that precedes Shema.
כגונא דאנון מתיחדין לעלא באחד אוף הכי איהי אתיחדת לתתא ברזא דאחד למהוי עמהון לעלא חד לקבל חד
Just as they unify above with Echod, thus, so too, He is unified below in the mystery of Echod. To make with them above, one to receive one...
That each of these worlds, above and below, is like a fractal or chiral form to each other ultimately manifesting G-d's unity in an infinite form.
And as the text continues, This fulfills the mystery of G-d is one and His name is one. That name (שם) is an abbreviation for heaven and Kingship (שמים ומלכות), meaning the spiritual domain of the angels above and our physical, material domain below, the earth.
A similar idea is expressed in the blessings preceding morning Shema which mention how the ministering angels of Heaven listen to and parallel our words when reciting Kadosh, Kadosh, Kadosh, etc.
This idea, that there are similar worlds, above and below, is part of G-d's system for the structure of all creation. It is based on a kabbalistic doctrine related to the doubling letters in the Hebrew alphabet. The explanation of this can be found in Sefer Ginat Egoz by Rabbi Yosef Gikatilla.
The next assumption is in the form of a question asking, "why did He create finite number of worlds". Even here, the premise is not in keeping with many traditional Jewish teachings found in the kabbalah and Chassidut.
The finite worlds, which are described generally in Torah as the worlds of Briah, Yetzirah and Asiyah, correspond to the structures of the courtyard and enclosure of the Mishkan and Mikdash. These also correspond to human physical action, emotional qualities and intellect. The Heichal and Tent of Meeting correspond to the world of Atzilut, which is infinite, but is still a named world. Aztilut also corresponds to the soul, Neshamah. What is called Worlds without end, is referring to those unnamed worlds which precede Atzilut like is mention by Rabbi Chaim of Chernovitch in Be'er Mayim Chaim to Bereshit 1:1:73. They correspond to the Holy of Holies in the Mishkan and Mikdash and the Pintele Yid of the Jewish soul, which is described in Tanya as a piece of G-d above literally. (חלק אלוה ממעל ממש)
So there are other worlds with creatures similar to us according to traditional Jewish belief. And that leads to your closing question about if they received the Torah? And this is answered by the text of the blessing that we are required to make before reciting words of Torah each day.
אשר בחר בנו מכל העמים ונתן לנו את תורתו
That G-d chose us from all the nations and gave us His Torah.
That Israel is the one nation, meaning the nation of oneness who unifies G-d's name, like is expressed in the Shomer Yisrael prayer said in Tachanun which says:
שומר גוי אחד, שמור שארית עם אחד, ואל יאבד גוי אחד, המיחדים שמך כו׳
And this relates back to your opening question about why G-d created finite people to bestow good upon. One of the ideas associated with creation, is that one of the purposes behind creation is to reveal G-d's Kingship like is expressed on Rosh HaShanah. And like the expression of our Sages, There is no King without a nation like is found in Kad HaKemach of Rabbeinu Bechaye, Rosh HaShanah 2:3.
אין מלך בלא עם
There are other ideas related to this, like that Kingship within the Torah is also expressed through the King caring for, meaning bestowing good, to His people.
Another reason mentioned is that the purpose of creation is that we know Him, knowing in the sense that Adam knew Chava (Bereshit 4:1 והאדם ידע את-חוה אשתו). And since He both fills and transcends all worlds, ממלא כל עלמין או מלכותך מלכות כל עלמין וסובב כל עלמין, then to truly know Him, one must acquire both those aspects. And this is accomplished through learning Torah and fulfilling the mitzvot like is discussed in Tanya 1:37:2 and also by the Tzemach Tzedek in Derech Mitzvotecha 1:31.
The main issue isn't Infinite/finite, it's Perfect/imperfect; created/Non-Created. As Ramchal states, we can't receive His total good because we are created and therefore don't own our good, and the true best good is Him, and we are not Him.
His solution is to give us Himself.
May I recommend finding a shiur on the first perek of Derech Hashem.