Trying to keep the OP up to date with key information. PM me if something is missing.
Friend Codes (GWJ google sheet). Updated in May with character/island names.
Polygon online play guide, for multiplayer. Or here is their New Horizons Guide, with links on several topics. The first 7/14 day guides are great for starting, as well as many guides on multiple topics.
From the polygon guide above, but much discussed: Rock Hitting Guide
Stalk Market price predictors.
Original, with improved interface. Seems to have best numbers.
*Removed 2nd calculator that many reported inaccurate numbers with.
Weather (and shooting star) predictor.
This tool from Ninji is amazing. Once you find your weather seed from the 1 billion possibilities, it will predict rain/snow, sun, rainbows, Aurora borealis, meteor showers (big and small), as well as charting the shooting star times on your island to the second!
Finding your seed can be tedious. If you have a meteor shower and use a timer to track by the second you can get quick results. Otherwise, lots of entries to narrow down previous days can help. I was able to find mine with dates of meteors (no times) and Celeste visits, as well as 3 or 4 thunderstorm hours. The hour a thunderstorm happens can lock in an entire day's weather accurately without any other info, so those are useful. Same with rainbows, if you have any screenshots of those.
Flower breeding guides.
I've removed the old quick reference image because it's not accurate. Island native flowers and hybrids can be different from ones you find on Nook Mile islands. It's more complicated than originally thought.
This site has good explanations and breeding guides. I'll link to the Simple Guide, and you can read the more complex one from the site.
For blue roses, specifically, here's a step-by-step guide in image format:
Quick reference image for Redd art, with real/fake text descriptions. Spoilered image:
Old OP, pre release:
The special edition Switch system comes out Mar 13, a week ahead of the game. But it seems pre-orders sold out in the US in about 4 days. Good luck if you want one. Nintendo did an official unboxing video last week.
Just saw this Polygon article Monday about paths, cliff stairs, and other fun stuff gleamed from screenshots.
And previews have already mentioned co-op play, which I am most excited about.
Official web site launched today.