Samsung will launch the new phones in January 2021, according to leaker Steve Hemmerstoffer or @OnLeaks (via Voice). A standard version and an Ultra version are surely coming; a Plus variant is possible, but this leak doesn't contain any info about it.
As for the exact names, we aren't sure yet; Hemmerstoffer calls these phones Samsung Galaxy S21, but there are indications that the new models might carry the name Samsung Galaxy S30.
The leak also comes with renders of the standard and the Ultra models, showing them from all sides.
Not many details of internal specs were provided, but the Samsung S21 (S30?) will have a 6.2-inch, flat display (no more curvy edges) and will measure 151.7 x 71.2 x 7.9mm (plus an additional 0.1mm of thickness if you include the hefty camera bump).
The Ultra variant will have a 6.7 to 6.9-inch display with slightly curved edges, and an absolutely massive camera bump (we don't know the exact number of cameras on that thing, but Hemmerstoffer says it could be "up to four"). The Ultra will measure 165.1 x 75.6 x 8.9mm, with 1.9mm of extra thickness if you include the camera bump.
As for the launch, we don't know the exact time frame, but Android Central also claims that the launch is currently slated for January. Samsung typically launches S-series flagships in mid-February, so a January launch would be a bit of a surprise. It would also bring the launch closer than ever to Apple's iPhone 12, which launched later than expected due to the COVID-19 pandemic.