What phones are in the Dex mode?

Could you please elaborate on which smartphones currently support the Dex mode? I'm interested in understanding the specific models and brands that offer this feature, as I'm considering purchasing a new phone that can enhance my productivity and multitasking capabilities. Additionally, I'd like to know if there are any recent developments or updates to the Dex mode across different manufacturers, as well as any potential limitations or compatibility issues I should be aware of.