You might want Iterators.product
julia> a = collect(0:5);
julia> collect(Iterators.product(a, a))
6×6 Matrix{Tuple{Int64, Int64}}:
(0, 0) (0, 1) (0, 2) (0, 3) (0, 4) (0, 5)
(1, 0) (1, 1) (1, 2) (1, 3) (1, 4) (1, 5)
(2, 0) (2, 1) (2, 2) (2, 3) (2, 4) (2, 5)
(3, 0) (3, 1) (3, 2) (3, 3) (3, 4) (3, 5)
(4, 0) (4, 1) (4, 2) (4, 3) (4, 4) (4, 5)
(5, 0) (5, 1) (5, 2) (5, 3) (5, 4) (5, 5)