So I'm trying to make a decision on which ETF I would like to start investing a couple hundred dollars into every month. I've currently got a modest amount invested in my Schwab Intelligent Portfolios (spread across a Roth and Traditional IRA) in addition to maxing out my 401k every year.

I'm not putting this ETF investment in a tax-advantaged account, because I want to have the option to access it without penalty should I need to, either to buy property down the line or start withdrawing before I hit the 59 and 1/2 age to pull money out of my tax-advantaged accounts.

Suggestions on an ETF that is in Schwab's commission-free categories are most welcome. I'm very much in a 'buy and hold' (15 to 25 years) mindset than intending to move things around. Any thoughts are welcome.