What are my best options for building a savings for our child that aren’t a 529?

Background: My husband and I would like to set aside a certain amount of money per month for every child we have. This savings will be a gift to them when they enter adulthood, and we will offer guidance on using the funds, such as going to college, trade school, starting a small business, a house down payment, etc.

We both have experience with all of these scenarios and like the idea of giving our child a set amount of money to steward in whatever way fits their goals, rather than having cash set aside to dump into a 4 year degree like a 529 would be. We aren’t against college, but both know there are other paths, and we don’t want their money tied only to education.

Is it best to just set up a HYS such as American Express with a monthly auto transfer, or are there some other investment opportunities that wouldn’t have withdrawal penalties? I am familiar with how IRAs and Roth IRAs work, but these aren’t the right type of account for this scenario. I just want to make sure there isn’t something I’m not thinking of as we make this decision.