This sounds pretty good
An unused page I had in mind was an iceberg chart. This idea was mainly fueled by the great Super Mario 64 iceberg as at the time there were stuff like the Gigaleak and Wario Apparition trending.
The iceberg chart on my site would've centered around any possible theories that people have made about my OCs and their canons or lore crumbs that I've dropped here and there but never really sat down to think about. The further down the iceberg goes, the more obscure the entries get. Some having a good idea and others not that much thought of.
Another unused idea was including some big graphics for certain parts of the page for aesthetic purposes. Like for instance, the error or "not found" page would have this graphic of somebody shrugging or a computer with a big red X over it.
These were around the time I had WonderNet as a site and it was on Neocities, long before I switched to Nekoweb and had both Eric's Corner and aspects of WonderNet merged together.