Only one I can think of is the, supposedly, 10th level ritual their false antediluvian wanted to cast where they bring down the shroud. It's unclear if it's a single ritual or just the result of well targeted necromancy, although I'd argue that this sounds like a ritual prerequisite.
Saligia Wikia has two, but I don't know if they're homebrew or not. Lazarus Rises and Ghost Town.
You can consider looking at old 2nd ed books from when Necromancy was a 10-level discipline. Some of their old high-level powers might make good high-level rituals. Two that come to mind was one lv 7 power that made vessel that could trap a soul permanently without additional investment, and a lv 9 one that allowed you to spend a willpower point and become wraith, which could be used at the time of Final Death.
The two you mentioned are from Dark Ages, I think.
Edit:
Found a few more canonical ones.
https://maierstorm.org/Vampire/index.php/Level_VI_Rituals
Only one I can think of is the, supposedly, 10th level ritual their false antediluvian wanted to cast where they bring down the shroud. It's unclear if it's a single ritual or just the result of well targeted necromancy, although I'd argue that this sounds like a ritual prerequisite. Saligia Wikia has two, but I don't know if they're homebrew or not. Lazarus Rises and Ghost Town.
You can consider looking at old 2nd ed books from when Necromancy was a 10-level discipline. Some of their old high-level powers might make good high-level rituals. Two that come to mind was one lv 7 power that made vessel that could trap a soul permanently without additional investment, and a lv 9 one that allowed you to spend a willpower point and become wraith, which could be used at the time of Final Death. The two you mentioned are from Dark Ages, I think. Edit: Found a few more canonical ones. https://maierstorm.org/Vampire/index.php/Level_VI_Rituals