Some Siddurim include a special prayer which is inserted at the end of the Amida before taking the three steps back. The translated wording of this prayer is: “May it be Your Will Hashem our G-d and the G-d of our forefathers, that the jealousy of others should not come upon me, nor my jealousy upon others; and that I should not become angry today, nor should I anger You; and may You save me from the evil inclination and may You give me humility and the fear of sin. Our King and G-d, unify Your Name in Your World and build the Holy Temple.”
There is another prayer inserted in many Siddurim which was composed by the Hida, and is also recited in Tashlich as well as by Ashkenazim when they bless the new month. In this prayer we ask Hashem for several things including a good life, longevity and peace and we then ask for Hashem to grant us fear of sin, a love of Torah and fear of Hashem. It would seem that fear of sin and fear of Hashem are redundant requests, but only once someone is granted a love of Torah and can truly understand Hashem and His commandments can one truly revere Him.
* * *
The Rama writes (Orah Haim 123:1) that after one says “Oseh Shalom Bimromav”, the Ashkenazic custom is add another prayer in which one asks for the Temple to be rebuilt (“Yibaneh HaMikdash”). The HIDA, however, writes (Birke Yosef 123:2) that the wording should actually be “Shetivneh”, that Hashem Himself should build the Temple. If we ask that the Temple simply be built, it may potentially be destroyed, however by asking Hashem to build it, we are assured that it will be eternal.
Summary: There are two prayers one can insert before finishing the Amida. The Sephardic custom is to say “Yehi Ratzon Shetivneh Bet HaMikdash” immediately after the Amida.