Much like how combiners wars are a nod to the past so too are some of the links below with a look at potential Action Master designs using combiners as action figures, some behind the scenes info from Transformers: The Movie and 35+ year old commercials from Japan that feature many of your favorite G1 Transformers before they became Transformers. There are also links to galleries to the first 3rd party Grimlock, Prime 1 Studios Age of Extinction statue line, and a stop motion video.
As for reviews, the links include Hasbro's Combiner releases of Cyclonus, the Protectobots, Stunticons, along with Robots in Disguise Jazz & Drift, Playstation Optimus Prime and Masterpiece Star Saber. For third party releases there are a ton of reviews to go with their now overkill output. Iron Factory and 3DX has three releases of their legend scale lines. ToyWorld completes their not Throttlebot combiner after over a year of nothing on that front while also releasing a solid take on not Astrotrain. The number of not Dinobots in the works has reached at least six lines that I can think of including two of them being combiners. Probably need to develop a cheat sheet to keep up at this point. Warbotron has completed their not Bruticus combiner that looks spectacular while Unique Toys reaches the halfway point on their not Terrocons. Those are just some of the many reviews linked below.