you can't imagine how many of these plates I sold between between the 1995 and the 2000!
I can tell you some name of the possible producers: Ragazzi, Tiozzo, Trevisan, Mosaico Veneziano.
Moretti, with his name and history, is on an higher price range and they sell a lot less in quantity.
For this style of multicolor murrina composition, they use standard murrina canes, that they can buy just ready cutted in small pieces to be use immediately. Therefore for these plates is very hard to say who is the company, due to the murrinas are the same.
May be that you can check the finishing (coldwork). Probably the Tiozzo ones are more "hand finished" (Claudio Tiozzo is a very good coldworker), the Ragazzi and Trevistan ones are really similar, and the Mosaico Veneziano productions are a little cheaper.
There are also other companies, but these four names had the 80% of the market for these productions during the last 15 years and they are still in production.
PS. Ragazzi and Trevisan in the last 7-8 years should feature the official "Murano mark". I'm not sure if Tiozzo is in the consortium and for sure Mosaico Veneziano is not.