They are easy to find here -
https://www.antpool.com/poolStats.htm - just by looking for the ones that are only 25 BTC and no change. a bunch of orphan ones as well. so how do you mine a block with no transactions.
It is not hard to do, you simply do not include them.
It is just plain bad for bitcoin, all around.
The worst part is any benefit of including 0 transactions is miniscule, by not including transactions your found block is smaller which results in hundredths of a second faster block propagation time and perhaps a 0.0001% better chance your block does not get orphaned.
It's selfish and slows down transaction processing for everyone.
As bad as the centralization the discus fish and ghash create is, at least they mine big fat blocks with many transactions...
If Bitcoin survives as it is currently designed, the day will come when transaction fees HAVE to be the large part of the block reward, as the block reward will continue to diminish in size. For those that haven't been around, blocks started out at 50BTC. Now they are at 25BTC, and the time isn't too far off when it'll halve again to 12.5BTC. Any pool that purposes puts out blocks without transaction fees is hurting Bitcoin.
The same goes for any pool that grants all transaction fees to the block winner. That can't continue.