Elite and starglider were both wire frame hidden line removal 3D engines that ran in real time. Even before that you have freescape games like Castle master that were solid and lit 3D engines and these were on 8-bit machines.
Sorry to be a pedantic git, but Driller (the pioneer first freescape game, was out WAY after Elite AND Starglider.)
Though you're right, these games had 'proper' 3D engines, and were not just like 2D-viewed-in-3D or whatever! Great impacts on the future of gaming were made by these names!