Ruflux
Ancient Mariner
If you ask me, the only example where they even get close is probably Be Quick or Be Dead, and that's a total one-off. But what a glorious one-off it is. Although I do suppose Purgatory also qualifies, if not even more so.I don't know man. I really don't find Iron Maiden thrashy at all.
Somewhere in Time isn't really aggressive enough to qualify, even if the average pace of the songs is probably higher than on other Maiden albums. The guitars are so effects heavy that they don't really bring enough grunt to the riffs to make them stand out and the title track is largely built around the main harmony, not a riff.