Some examples:

• baptism for the dead (New Testament)
• drink offerings (Old Testament) I think – might be in the BoM

I know there's one where in the BoM they hang someone from a tree and then cut it down. This *might* be in the Old Testament too.

There was also a feast / ceremony of mourning somewhere in the BoM. I made a note of it in my BoM notebook, or one of my scripture notebooks pointing it out.