A new “VSTAR” trademark has been filed by Pokemon. It’s under the same usage terms as recent Pokemon TCG sets, meaning it could be an upcoming Japanese set. Trademarks are discovered five to six months in advance, so this would release around April or May if it’s a set.
The next Japanese sets are Single Strike Master and Rapid Strike Master on January 22nd and then an unnamed March set. We also know of three trademarks for sets that could release around March: Matchless Fighter, Silver Lance, and Jet-Black Spirit.
In the past trademark filings have also been used for new types of TCG mechanics and even the Fairy type.