a = torch.Tensor([[1,2,3],[4,5,6],[7,8,9]])
b = torch.Tensor([[1,3,7],[2,4,8],[3,7,9],[4,5,6]])
c = torch.Tensor([[1,2,3],[2,4,8],[3,7,9],[3,5,6],[7,8,9]])
d = torch.cat((a,b,c))
torch.Tensor([list(item) for item in set(tuple(row) for row in d.numpy())])

tensor([[1., 3., 7.],
[3., 7., 9.],
[2., 4., 8.],
[7., 8., 9.],
[1., 2., 3.],
[3., 5., 6.],
[4., 5., 6.]])
This is not the best solution but it will do the trick