The website that offers the best information on Tutankhamun's lifetime achievenments is.
Lots of folks don't appreicate the lifetime achievements of Pharaoh Tutankhamun, it is a shame they don't. If they did perhaps he wouldn't be considered such a boy king. Of course everyone claims that Pharaoh Tutankhamun had very little to do with these building efforts. But most of these people are applying 20th century AD realities to him, not 14th century BCE realities. However most of the work that survives to today, were usurped by both Ay and Horemheb not long after Tutankhamun's death. In fact many that Ay usurped were then usurped by Horemheb, and some of them were then usurped by Ramesses II.
A brief list of his known achievements
He built at Karnak and Luxor.
At Luxor he continued the construction of the entrance colonnades of Amenhotep III's temple. (The famous picture of Luxor where you see all the pillars is the entrance colonnade that Tutankhamun mostly started, decorated and finished.)
He richly embellished the temples with images of Amun (in the image of Tutankhamen), Amunet, and Khonsu.
Even more statues and sphinxes depicting Tutankhamun himself.
A small temple in Nubia.
A pair of granite lions.
He restored the religion of the Old Gods to Egypt and reopened closed temples of all the Gods that had been proscribed.
He restored the names of Amun, and other proscribed gods that Akhenaten had removed.
He repaired the ruined temples that Akhenaten had wrecked.
He moved the capital to Memphis, built there and in Thebes.
He began construction of his tomb near that of Amenhotep III"s.
Built at least one colssal statue of himself that was to stand at his mortary temple started at Medinet Habu.
He also oversaw the reburials of his Armana relations that where originally buried at Armana.
He also according to a chest found in his tomb was involved with war. This chest is the only surviving remains of his war exploits where he led, or was associated with battles in Nubia, and Syria. In Syria there is increasing acceptence that he was with Horemheb at the battle of Gezar, AKA The Eastern Expedition.
There is also the mighty interesting report by the King of Hittite, Mursilis II, about the death of Egypt's King at the time of Egypt's defeat of a major battle against Hittite. (considered to be at Aleppo.) The Pharaoh, King Mursilis II referred to is considered to be Tutankhamun. He would have been between the ages of 17-19, it was during his last year of life. Scholars are also sure that his campaign in Nubia was more successful than the Syrian one(s).