Sam2
Your thinking of the Shomronim or Samaritans.
They have “Sifrei Torah” that they write in Ksav Ivri that are basically the same as ours except for a few differences, a big one being that there is a commandment in theirs to build a ‘Beis hamikdash” on Har Grizim.
They also do not except what we call the Torah Shbaal Peh because they were separate from Klal Yisrael already in the times of Tanach WAY before the times of the Tannaim and Ammoraim.
The Karaites are similar to what was known in the times of the second beis hamikdash as the “Tzidukim” who were mainly Cohanim and rejected the teachings of Chazal and the notion of Olam Habbah as well. After the Churban the Tzdukim disapeared and did not leave over any known writings as their version of Judaism revolved only around serving in the Beis Hamikdash whereas the Perushim (followrs of Chazal- Pharisees) still believed in learning Torah and an afterlife even after the Churban and still had what to hold on to.
There were other sects of Judaism that disappeared after the churban as well such as the Essenes who wrote the Dead Sea Scrolls.