The MLPs generally are sold by brokerage houses. IMO, they pay the broker a large commission from your account and my experience is that they are crud, but they often have very flashy packets for buyers. MLPs are also setup for storage buildings, movies, etc. IMO, they are traps to catch your money so I don't buy them.
Bonds are different. You have a choice of individual bonds, like EE, I bonds, individual issues (not very diversified), and bond funds (index and not-index). Currently, I favor the short term investment grade index at Vanguard as it is diversified and has a short duration, meaning if interest rates go up, the fund will have a shorter time period to recalibrate to the new rate structure, unlike an intermediate or long term fund. Our current low interest rate time means that bond funds purchased now will probably decline, corresponding to their bond duration, as interest rates eventually rise (But then, you will have the benefit of the new rate). No one knows when that happens.