Unfortunately, most of what you find when searching for a corner vanity table are not makeup tables at all, but are actually sink basins that are designed to be mounted in the corner of the bathroom.
However, if you look hard enough, you can find that there are specially-designed vanity tables that go in the corner of the room. The difficulty is what to do with the mirror.
The centerpiece of any vanity table is the makeup mirror. Since most vanities sit back against a flat wall, the mirror can be mounted at the back edge of the table (and even secured to the wall for stability). However, with the corner vanity table, the mirror cannot go all the way back.
To work around this, look for a mirror that is relatively narrow, and preferably one that is on a single-leg pedestal rather than one that mounts to the table itself.
You may be better off purchasing a standalone corner vanity, then finding a makeup mirror separately, as you will have a much wider selection of styles. This will make it easier to find something that matches your decor.
The final difficulty in finding a good corner vanity table is the space under the table where your knees go while you put on your makeup. Because the corner is so narrow, this can make the space rather cramped. Any space-saving you get by using a corner-vanity is lost in the inconvenience of finding one and having it be too small.
Rather than finding a corner vanity table, consider finding a standard vanity that fits your room without being in the corner.