Look into small and mid cap funds as well as emerging market funds. (thecollegeinvestor.com)
In my 401k I have always allocated a greater percentage of my portfolio into mid cap funds because they seem to be riskier and have a higher upside. (money.stackexchange.com)
Australian small and mid cap funds however, were out - performed by the market index in just 29 % of cases which is an interesting potential trend. (wealthfromthirty.com)