re: Recommendations on index funds for taxable account?

The Roth holdings don't have to be tax efficient, the Roth wrapper makes any holding tax efficient. If tax efficiency is of the utmost importance to you the total market types of funds/ETFs, ie total market + international will be very tax efficient and low costs. I hold a significant position in an international small cap ETF in taxable and the tax effect has been negligible. If you hold more volatile asset classes in taxable they can provide more tax loss harvesting opps over the years as well to offset future capital gains and QDI. I don't like losing money, but in an IRA/Roth there are no tax loss opps, and those in taxable have saved a lot of taxes over the years.