These are the different categories of mutual funds:
Equity funds
Debt funds 
Hybrid funds
Solution-oriented funds

Other funds like FoF, ETFs, and Indexed Funds, etc.
All of the above-mentioned funds can have further sub-categories, which we are not discussing further.
Out of the above-mentioned categories- Equity investment is most preferred and is considered to be most reliable and then comes the debt funds. Even though investment in mutual funds is considered less risky, there are some funds in which investment can be avoided or played safe:

Solution-Oriented Schemes- An entire category to be avoided:
Solution-oriented scheme include Retirement benefit plan and children’s fund, the major drawback for investment under this category have a lock-in period of 5 years, which will definitely block your fund, which would have been utilized somewhere else in a better way and with better returns.

Banking and PSU funds:
Traditionally these funds are considered to be reasonably safe as they have the name of PSU’s and banks. The major drawback of these funds is limited growth and bitter truth is that the government may not come for the rescue when these units collapse.

Debt Funds- Medium Duration and above:
Investment in these Debt funds ranges between 3-7 years. Though investors are attracted more towards debt funds, investment in medium durations is difficult to manage. SEBI even provides an escape clause of adverse situations. The funds can reduce the duration as low as 1 year. In short, these can be dynamic bond funds but with more constraints. Almost all retail investors can avoid this category.

Conclusion: While investing your money in mutual funds, you should be well aware of where and how will your money grow. Lack of information/ hurry in investing might land you a huge loss. So, just be well aware and informed.