Who do you propose things to? The boss? What if you've proposed numerous things but they've been turned down?
If it's some bit of refactoring or performance improvement, then the tech team or engineering manager.
If it's a feature, perhaps the designer or product lead.
If it's marketing related, then the marketing team, mostly to see how they work and whether it affects them as expected.
If it saves money... then not finance, but whoever takes credit for cost cutting.
If you've been turned down, why? Is it not helpful? Unnecessary? Are you misunderstanding the situation? Are you making them look bad? Do they not trust you?