VEA and VWO are also good for low-expense international diversification.
More aggressively, VIOV and VBR target "Small Cap" "Value", stocks, 1 - 2% of the total market that are smaller companies with more low-growth prospects. There is academic research to suggest that there may be some higher-risk but even-more-high-reward for these type of stocks that is consistently underpriced by the so-called "efficient market hypothesis."
This is a backtest from 1972 where $10k in Total Market (~VTI) and Small Cap Value stocks were bought and Small Cap Value ended with $7.5m against Total Market $2m, while retaining better Sharpe and Sortino ratios.
I would throw in Avantis Small Cap Value (AVUV) as a contender.
Avantis' funds are index-like in that they pick stocks by screening the universe of market-cap-weighted stocks using factor-based screens, rather than active management. Their algorithms use profitability, volatility, size, and value as factors, and mix in the momentum factor (basically, stocks that go in one direction tend to move that way for a bit) to time trades.
The international counterpart is AVDV, and they have a whole range of funds for emerging markets and so on.
Avantis was founded by ex-Dimensional (DFA) people and their methodology is similar to that of the famous high-end mutual funds run by DFA. (Of course, DFA also has ETFs now.)
AVUV may perform similarly, but it is actively managed to the whims of Avantis' decisions and does not track an index. Thus it is also a 0.25% expense ratio compared to VBR and VIOV at 0.07% and 0.15% respectively.
Avantis: "this fund is an actively managed ETF that does not seek to replicate the performance of a specified index."
Avantis' funds use rule-based quantitative strategies that use screens and performance data to decide the fund composition and trades. Unlike actively managed funds, there's no human picking stocks or timing the trades. I'm sure they tweak their models a lot, but it's not a Peter Lynch situation.
Indexes like the S&P 600 (which VIOV follows) use similar screens for value and profitability and so on, and could be said to be "actively managed" [1]. Don't forget that indexes are typically "actively managed" as well. The S&P 500 is an example of an index that is essentially a human-curated list set up by committee. It's not the top 500 companies on VTSAX/VTI.
But indexes have a big downside in they they're not rebalanced so often. Avantis' funds can rebalance constantly (usually daily) based on their quantitative models.
More aggressively, VIOV and VBR target "Small Cap" "Value", stocks, 1 - 2% of the total market that are smaller companies with more low-growth prospects. There is academic research to suggest that there may be some higher-risk but even-more-high-reward for these type of stocks that is consistently underpriced by the so-called "efficient market hypothesis."
This is a backtest from 1972 where $10k in Total Market (~VTI) and Small Cap Value stocks were bought and Small Cap Value ended with $7.5m against Total Market $2m, while retaining better Sharpe and Sortino ratios.
https://www.portfoliovisualizer.com/backtest-asset-class-all...
That is only for those who could commit long term with conviction of their research and understanding, as there are periods of 10-15 years you could underperform Total Market: https://www.portfoliovisualizer.com/backtest-portfolio?s=y&s...