Are there sources for the concepts of Moshiach, Techiyas HaMesim, and Olam HaBah in Tanach? Thank you.
Sure there are.
Regarding Moshiach the Nevi’im are full of it. For example, Isaiah chapters 11, 12, 24 through 27, 34 through 37, chapter 40 until the end.
Regarding techias Hameisim – see tractate Sanhedrin 91b that elaborates and brings numerous verses regarding techias hamiesim. Some examples are, “See now, that I, I am He- and no God is with me. I put to death and resurrect” Deuteronomy 32-39. Also “ Then Moshe and the Jews will sing” in the future after the resurrection. It is also spoken about specifically in Ezekiel 37 1-14.
Regarding Olam Haba see Rambam Teshuva 8, that he beings a number of verses for this.