Sonic 3C 0517 proto -

It has a credits, a working zone playlist and more. Sonic 3 complete is a category yet this is not. Its a midground between S3K and S3A too which makes it an interesting game to run.

Same can be said for S&K + S3 525 proto. Yet it just doesn't have credits.

Both of them are just S3K with S3A physics. Why are we not seeing a leaderboard for these two prototypes of S3K?

They are trying to add every game and mod hack so they might be doing a poll or a meeting for choices for other games

From here: https://www.speedrun.com/knowledgebase/game-request-rules

Demos/Pre-release Versions/Prototypes If a page for the full-game is already present, we would suggest you send these requests to the moderators of the game in question, as they may add it as a category and avoid the need for an additional game listing. We may deny your request on the basis that we don't want two separate pages to track the exact same game, with the only key difference between the two being that one has less content or content of an earlier version. These are dealt with on a case-by-case basis.

Long story short, a prototype is highly unlikely to be added.

Also Sonic 3 Complete was added at a time where there was lack of consensus on how to handle glitchless runs. as you can see the board is practically dead, and most people will run glitchless on S3K.