Coming in October, wave 19 will include the Delta Flyer, the Klingon Bird of Prey IKS Rotarran, and Romulan ship RIS Talvath. I believe this is the first time the Delta Flyer has been made as quite such a small model, which could have its appeals if it works at a nice scale with one of the larger models of Voyager.
Wave 20, coming in November, includes the Constellation class USS Hathaway, the Kazon Raider Halik, and squadron of Romulan (or Reman) Scorpion class fighters. The Scorpion class are new models too.
Wave 21 is set for December release, and includes the Jem'Hadar fighter Robinson (the one the DS9 crew captured), a Bajoran lightship, and the Cardassian Dreadnought missile. I believe this will be the first ever model of the Dreadnought.
The first release of 2016, and the last one so far announced, wave 22, due out in January, will include the Defiant class USS Valiant, the Romulan ship RIS Pi, and the Andorian ship Kumari. This will be only the second time the Andorian ship has been released, following the recent Eaglemoss version.
In addition to the ships you can buy, Wizkids often also promote regular organised play events, where retails can order in themed packs to play the game ins-store. Several models have made their debut as prizes in these events, before later being offered as regular retail releases. The next event, due at the end of the year, will be the Temporal Cold War, which looks set to be Xindi themed, and the Xindi-superweapon looks likely to be a big model, like the previous Borg Cube and Deep Space 9 models.
Wizkids have sneakily displayed this model already, in prototype form, in a photo from their offices that they posted on Facebook. I've highlighted the interesting Star Trek bits below; as well as the Xindi weapon there's also a different big Borg Cube there, which appears to have a Sphere port. Thanks to Darth Duranium for pointing me towards this.
It's been a while since I've looked for release images of the Attack Wing ships, so, going all the way back to January: Wave 11 included the Romulan drone ship Prototype 01, Hirogen ship, Alpha Hunter, and Fighter Squadron 6, a group of three Federation Attack Fighters. All three of these are the first ever models produced of the respective designs - Although Eaglemoss has all three on their list for larger models, with the Romulan drone out already, and one of their most impressively detailed so far.
Here they all are, as packaged, and with all the contents of the expansions. You can get a better look at some of the cards with each ship in previews on StarTrek.com, here, here, and here.
Wave 12 onsisted of the Kazon Ogla's Razik, the Romulan warbird IRW Haakona, and a Tholian ship, Tholia One. StarTrek.com card previews: here, here, and here.
Wave 13 featured the Gorn raider, Gornarus, the Constitution class mirror universe ISS Enterprise (which was originally solicited as being in refit configuration, but by final release had reverted to the on-screen seen original configuration), and the Cardassian Galor class Reklar. This is the first, and so far only, model of the TOS remastered Gorn ship - The first widely available at least, it was previously offered as one of the prizes in an Attack Wing play event. StarTrek.com card previews: here, here, and here.
Wave 14 included the mirror universe NX class ISS Avenger, Kyana Prime, aka the Krenim Temporal Weapon, and the Oberth class USS Pegasus. StarTrek.com card previews: here, here, and here.
And wave 15 featured the Klingon Bird of Prey IKS Ning'tao, the Bajoran ship Ratosha, and the USS Prometheus. StarTrek.com card previews: here, here, and here.
That's all for now, but there are Attack Wing ships out every month, so plenty more to look forward to throughout the year!