The trilogy of classic isometric games from Bernie Drummond:

Batman (Spectrum)
Head Over Heels (Spectrum/C64)
Monster Max (Gameboy)

HoH is available in new super colourful port-o-form on the PC and bloody good it is too. Can't remember the link offhand, can't be hard to find.

And then there's Ultimate's (aka Rare) set of games for the Spectrum: Knightlore, Alien 8, Nightshade, Gunfright.

And finally Equinox and Solstice on the SNES by Software Creations (which means gorgeous Tim Follin music).