I'm not asking for you to reveal what coins you are solo mining, just curious of anyone is doing it. I've seen the odd thread in here of people solo mining but seems like not many people do.
For new altcoins, this can be done, but essentially it does not have any economic sense. If mining in the pool is possible, then it is better to use the pool. In general, it is better to mine liquid currencies and buy the liked altcoins.