https://www.bogleheads.org/wiki/FidelityThe Zero series is very attractive if you don't ever plan to move away from Fido, but as they are proprietary fund class, you aren't allowed to take them out on the town as it were... so if you buy them in a taxable account, it could create tax issues if/when you had to sell them to shift the account to another place (like Vanguard). Otherwise, if you're in it for the long haul with Fido, I'd look hard at those. If I was just starting out, I'd probably go 50/50 split between Zeros and the Fido index funds (below) now. But I haven't done the obsessive homework on the Zero funds that I did in the early days when they had their Spartan series (what the Fido Index funds below used to be called) so you'll want to review the Zero stuff for any gotchas that aren't immediately apparent from my cursory recommendation.
I personally have a 3 fund portfolio at Fido primarily consisting of:
Fidelity Total Market Index Fund (FSKAX)
Fidelity U.S. Bond Index Fund (FXNAX)
With a touch of:
Fidelity Real Estate Index Fund (FSRNX)
I have less than 2% in a few other silly holdovers that I keep from nostalgia (bought from the before times when I had no clue and and despite my total lack of knowledge are doing really well) and another couple of percentage points in cash (E fund/savings). I only mention this in the spirit full disclosure. ;)
