Examples of expansions that increase replayability without also increasing players’ cognitive load too much:

http://www.phantomknightgames.com/news/the-one-about-expansions/

A guide to pitching your board game to publishers (video)

How to get your game onto Tabletop Simulator–a step-by-step guide to the basics:

https://boardgamedesigncourse.com/how-to-get-your-game-on-tabletop-simulator/

Board game design advice for absolute beginners:

http://makethemplay.com/index.php/2020/05/13/tips-for-starting-board-game-designers/

Interesting and innovative win conditions and scoring methods–a Twitter board game design discussion:

https://twitter.com/robinwriting/status/1259495527105912832

“Hey you! You know that idea that you have for a new board game? The one you’ve been stewing over for some time now? Well...

GET UP AND GO MAKE IT!

Seriously! Grab some index cards, grab some pennies - whatever you need - and MAKE IT! You’ll thank me later.”

— Tim Blank

Downloadable Excel template for generating hex maps:

https://drive.google.com/file/d/1mEIh7WFxsntfiJ-Qy_qq5n9Ta3SseRyr/view

Three things to consider to get you in the right mindset before pitching your game to a publisher:

https://brandonthegamedev.com/3-things-to-consider-when-pitching-to-board-game-publishers/

Pointers for communicating your board game’s rules effectively (video)

Why do so many games have five resources?

https://compoundinterests.net/blog/why-do-so-many-games-have-five-resources

“If you are going to be designing a game, you need to be the biggest champion for that game. If you can’t sit there for three years and talk about this game and talk about how much you love this game and how great this game is, then no one else is going to get excited about that game.”

— Tim Blank

Pointers for getting published, and the things you should be doing to make it happen:

https://twitter.com/emmalarkins/status/1258091971425402880

“Though it might not be required, writing a good rulebook can give you a leg up in not only getting your game published, but getting it published right. If you can’t communicate how your game is played to the publisher, they can’t communicate it to the world.”

— Emma Larkins

An argument that “challenge” is the key to a game that sticks with players:

http://www.phantomknightgames.com/news/eat-your-vegetables/

Board game designers share how they incorporate replayability into their games:

https://design100.org/60-replayability/#

Handy printable sheet with game design axioms to remember

How to playtest your game, plus how to work with playtesters and developers (video)

Lots of tips for funding and publishing your first board game, stated bluntly:

http://tabletopbackerparty.com/funding-your-first-game/

Some thoughts to help you find the motivation to get started turning your idea for a game into reality:

https://brandonthegamedev.com/how-to-turn-your-ideas-into-reality/

A comparison of Tabletop Simulator and Tabletopia, with pros and cons for playtesting on each:

https://firsttakesomedice.blogspot.com/2020/04/prototyping-and-testing-virtually.html