Can I post a model or sprite early?

[pompom454]

No, you would have to wait until the game comes out especially if it is for a console. TVGR likes to wait just in case someone submits fake graphics for an upcoming game (and they have done in the past) or in a couple of occasions the publisher/developer asked to wait for a certain amount of time. If it is just you working on the game, it really depends on the game and where you are uploading the game, having something on Steam or EGS is different than itch.io. Besides you could change your mind and re-work your model/sprites. After all there have been many cases where the graphics completely changed in development so it would look a bit silly uploading it now and then go "oh, I can do better than this" or "this character doesn't suit the level/map that I just redesigned" or even "this character looks a bit too close to such and such famous copyrighted character or looks like something that could offend people, I'll go change it to be on the safe side".

If it had a public demo and is notable enough for the site (e.g. Pizza Tower) then you could upload it. Maybe an Early Access game at most but ask the staff first.

Regarding SpriterTheo's point, the What Makes a Good Submission page is a little bit outdated as there are prototypes on the site and even hacks/homebrews. The prototypes were uploaded years after their release date and some of these are unreleased games that were going to come out but they never did whether there were development problems, the publisher closed down (in recent times even a closure of an online service e.g. the 3DS eShop) or in a few cases almost ready to hit the shelves/put on the server but got a last minute cancellation (usually cartridge costs, publisher changed mind, failed certification or real life issue). There are also some unwritten rules as well. Apart from that, it is really helpful even if depending on the genre or system would be difficult to completely follow the instructions (e.g. a game rendered in 4K and the icon has to fit 240x125, a generic sports game).

Besides pre-order of games or other, how about the beta, the alpha, or the demo?