Are there any Thunderbolt 2 external DVD drives?
You won't find a Thunderbolt 1 (much less and Thunderbolt 2/3) to an external DVD drive because there simply isn't any need to create one as USB 2.0 has more than enough bandwidth to accommodate even the fastest DVD drives on the market.

To understand why, we have to understand that the fastest DVD you will find is a 24x unit; most will be 16x.  The base write speed is 1x and a 1x speed is 1.32Mb/s so a 24x unit is about 31Mb/s.1

USB 2.0's transfer speed is 280Mb/s or about 35MB/s 2 so even the theoretical fastest DVD drive that you will ever find is less than the max limit of a USB 2.0 connection which, for all intents and purposes, has been obsolete since the beginning of 2009 (USB 3.0).3

There just isn't a need to create a DVD drive with a modern, high speed data transfer interconnect because it's a dying technology and it's fastest transfer rate doesn't even begin to exceed what is already backwards compatible with USB 3.0


1 Wikipedia Modern compact discs support a writing speed of 52X and higher, with some modern DVDs supporting speeds of 16X... 

2 Wikipedia  USB 2.0 was released in April 2000, adding a higher maximum signaling rate of 480 Mbit/s (High Speed or High Bandwidth), in addition to the USB 1.x Full Speed signaling rate of 12 Mbit/s. Due to bus access constraints, the effective throughput of the High Speed signaling rate is limited to 280 Mbit/s or 35 MB/s.

3 Wikipedia The USB 3.0 Promoter Group announced on 17 November 2008 that the specification of version 3.0 had been completed...