The handheld guns from the right: MG42 (oldie bur goldie!), Zijiang M99 (there HAD to be something obscure!), Mossberg M590 with some aftermarket add-ons like this bayonet-lug: https://www.flickr.com/photos/45307044@N02/15601587821/ .
Edit: Just found out, that there is a M99 in "Girls Frontline". It's obviously not so obscure as I thought.

Well looking closer in the image, that's an Accuracy International AS50.

d_Anjou said:

Well looking closer in the image, that's an Accuracy International AS50.

I was so happy to find something not being a Barrett or a NTW 20 after googling antimateriel rifle, that I didn't look close enough.