Hitman Airsoft gives a rather very quick view of the Beretta M9 HG-190 Gas Blowback Pistol made by HFC... "New from HFC is already available. Sophisticated design and low price GBB Beretta M9 HG-190 has a metal slide and a plastic frame. The model with a plastic case is delivered. The model runs on green gas and has a blowback function."
A suppressor with tracer unit for the Tokyo Marui M9 Gas Blowback Pistol demonstrated by Airsoft Shien... "Manufactured by RGW airsoft, Designed by Airsoft Shien, This KAC Style XM-9 Suppressor is designed for Tokyo Marui M9 GBB Pistols.
Comes with Supressor, Steel M9 Outer barrel with QD Slot Cut, and internal Spitfire tracer unit built by 5KU."
Airsoft Atlanta got some M9 GBB Pistols from G&G Armament back in stock. Spare magazines are also available to purchase as well... "Got a batch of @ggarmament M9 gas blowbacks. Custom carrying case included. Restocked on other BBs and G&G products as well. Check it out!"

Another M9 Beretta-style Gas Blowback Pistol from Saigo gets reviewed by Airsoft Review en Español. This costs €74.95 and is mainly made of Polymer. It has an initial muzzle velocity of 300fps and comes with a 25-round BB capacity gas magazine. This is available at some airsoft retailers, especially in Spain.
Cesar of 0'20 Magazine reviews the Secutor Arms Bellum Gas and CO2 Blowback Pistol. Based on the M9 pistol, it comes in black and bronze colours. A full metal airsoft pistol, it has an adjustable hop-up and comes with a CO2 magazine. Cesar does a takedown of the Bellum and also showing how to change the nozzle.
Evike.com feature that custom M9 GBB Pistol that uses the Poseidon Air Cushion Tech under the Matrix brand... "Poseidon has taken their cutting edge 'Air Cushion' technology, already very popular in the field of AEGs, and modified it for use in gas blowback pistols. The results don't disappoint. Able to shoot accurately up to 180 feet, the Poseidon BW9 is one of the most accurate and furthest shooting pistols on the market.
Evike.com got in stock the Matrix Elite M9 GBB Pistol. A clone of the Tokyo Marui M9 GBB, you got some choices of black and silver or full metal or not... "Derived from the venerable M92FS, the American Military spec. M9 pistol was the next iteration of the standard issue US military sidearm. When slated for replacement, the 1911 platform had already served the US for over 50 years.
Evike.com are expecting the arrival of the new CYMA CM126 M9 AEP in December 2017 and are now taking pre-orders. Based on the Marui AEP system the slide is metal whilst the lower frame is made of polymer. It has full and semi firing modes with adjustable hop-up. It uses the 7.2v NiMH AEP battery just like the other Marui AEPs.
USAirsoft reviews the M9 Gas Blowback Pistol made by KJ Works. This airsoft pistol was released in 2008 and has a full metal slide and frame. Magazine has a 26+1 capacity, ambidextrous safety, metal barrel, metal guide rod, and has a muzzle velocity of 330-340fps on 0.20g BBs using Green Gas.
Arsanus does a tutorial video to help you install the RA-Tech NPAs into WE Airsoft M9 Gas Blowback Pistol... "An In-Depth Tutorial on how to install a RA-Tech NPAS into your Gas-Blowback Pistol. This method should work on most Tokyo Marui/WE Gas Blowback Pistols and WE Open Bolt Rifles.
The Airsoft Pistol shown in the video is a 'WE-Tech Full Metal M9 Heavy Weight Airsoft GBB Pistol'.