I have a hybrid card-dice game. I know I have to copyright the rules text, the card text, and any graphic artwork on the card face and/or card back; trademark the name and logo of the game, any logos, any character likenesses in the artwork itself, any slogans (I'm creator-manufacturer so far and see myself having to market this myself, so yeah slogans and ad campaigns -- but waaaaay far future); and I know I have to patent both the card and the game mechanics. Thing is, How do I patent the game mechanics if I've already outlined them in the rule book? Or am I overthinking this?
The USPTO is still issuing patents for card games and board games by the flow has slowed over the last few years. I filed a patent application for a board game for a client and it was essentially rejected as being abstract as a "methods of organizing human activity”. This is a phrase plucked out of a SCOTUS case (Bilski) that, in the opinion of many, is taken out of context to go crazy rejecting things. A later SCOTUS case (Alice) has added to the wholesale rejections and invalidation of things that would not be considered abstract by anyone 20 years ago.
Criss cross poker casino card game with middle bet and five card bonus bet US 9564016 is an example of a recent patent on a game involving cards and dice. You can look up more at the USPTO patent search with a search string [CPC/"A63F1/00" AND DIE AND CARD].
You can look at these as a start in searching the novelty of your ideas. I'm sure you know that you do not need a patent to market a product. I think most games like this are protected reasonably well by trademark, but that is not my field.
Many countries only grant patents for inventions that solve technical problems. Gameplay or game mechanics of a card game do not solve a technical problem, so you cannot get a patent for those. In the European Patent Convention this is explicitly laid down in Art. 52.c:
(2) The following in particular shall not be regarded as inventions within the meaning of paragraph 1: [...] (c) schemes, rules and methods for performing mental acts, playing games or doing business, and programs for computers;
Patenting it in the US perhaps is possible.
As The Europeist notes, patents for games isn't possible in many countries. I do believe it is possible to get a game patent in the US. However getting patents is not easy or cheap. The best way, by far, is to employ a patent attorney or agent with experience in game patents. It is possible to file and obtain a patent without professional help, but it is very likely such a patent will provide weak protection and is much less likely to actually get granted.
Just to note, you certainly don't need to obtain a patent to market your game. The patent just provides some protection from someone marketing the same or a similar game.