the most request model and format

i would advise an obj is good format. The reason is an obj can be used in maya ,3dsmax,blender . The obj is great way to import and export into other well known 3d packages. Enabling the end user to import there models whether using 3ds max or maya ect

I agree OBJ is a good base model, but you really should consider converting it into a few formats. Native formats are great for buyers who use that platform, yet additional formats help when converting or importing things into other applications.

Hello Hamza,

I'd suggest taking a look at a few of our infographics, regarding formats, pricing ranges and other info (there's quite a lot, to be honest). Should find that useful!
https://www.cgtrader.com/blog/low-poly-3d-models-vr-and-you-how-to-ride-the-wave-in-2016

https://www.cgtrader.com/blog/infographic-best-selling-3d-models-and-practices

Regards,
Eddie, CGTrader

thank you very mush