The NCASE M2 is an offshoot of the M1EVO, which wasn’t well received by the SFF PC community and ultimately was discontinued. The M2 is the case we should have gotten with the M1 EVO.
SSUPD Meshroom S v2
SSUPD Meshroom S is a 14.9L vertical sandwich layout SFF PC case with an all mesh external design similar to the popular Meshlicious. The case leans more towards liquid cooling with limited CPU air cooler clearance compared to standard reference layout cases of similar volume. You can also install ATX/MATX motherboards with some caveats… Still this makes the SSUPD Meshroom S one of the smallest ATX compatible cases available.
DAN C4 SFX v2
The Dan C4-SFX v2 will be 13.88L in volume and will support only Mini-ITX motherboards, has support for 280mm liquid coolers, 145mm air coolers and 3.7 slot full length graphics cards.
Fractal Ridge
Fractal Ridge is console layout Mini-ITX case at 12.6L in volume. The case uses steel construction and comes in black or white variants. The Ridge is priced at US$129 / £129 and available from numerous retailers.