Hm...I have some good memories related to Fear of the Dark (I've gotten into Maiden around the time it came out), but I don't know if I'd call it underrated. There are some good tunes in there, but a lot filler too, imo. And I don't like the way it sounds at all.
Out of curiosity - what would be your 8 songs...?
Be Quick Or Be Dead
Afraid To Shoot Strangers
Fear Is the Key
Childhood's End
Wasting Love
The Fugitive
Judas Be My Guide
Fear Of the Dark
I expect all except The Fugitive to appear in my Top 75.
I say underrated because most people rate it pretty poorly. i remember it coming out and it being 10 times more powerful than No Prayer. It was their first album in the CD age, so at 12 tracks, they typically would've weeded out a couple of extras. You could add in From Here To Eternity and Chains Of Misery to round out a pretty good 10 track album.
Yeah, I guess on average now people don't rate it super-high now...I do however remember it was received quite well when it came out (at least in Italy/Europe), based on the reactions I witnessed myself, and in magazines at the time. As for me, I enjoy it better than No Prayer, and it arguably has 2-3 songs that have become well established in their live sets.
Of the songs you mention, I no doubt agree with Be Quick or Be Dead, Afraid, Judas Be My Guide and Fear of the Dark..
...as for the rest, Fear is the Key is kinda cool, Wasting Love was something a little different for them and I enjoyed it back then, and Childhood's End starts very promising (with that tom-heavy drum pattern weirdly reminding me of early Marillion), but I feel it doesn't quite deliver on that promise. All fine Maiden songs, but nothing that truly stuck with me over time (and unlikely to find their way in my top 75). The Fugitive is just ok...
Anyway, again, despite being more towards the bottom of my Maiden rankings, FOTD is an album I have some fondness for, clunkers and all