I would love to see black variants of:
TRG Series
Mk20 Series
ACP-C2 .45
AKS-74U
AKM
Mk18 ABR
Vermin SMG
RPG-42 Alamut
PO7 9mm
P99 9mm
Mk200
Zafir
Mk14

And would love to see a grenade launcher variant of the AKM, and maybe even make a RPK by making a version of the AKM where the Barrel is longer and it uses the AKM Drum Magazine

Black, Blue and ACU versions (and without flags) of:

Modular Helmet
Military Cap
A version of the heavy NATO vest without a flag
GA Carrier (Rig, Lite and GL Versions)
Vest (Press) (Without the "Press" name on both blue and black)
The new Vests and Helmets from Contact
A retexture variant of the Thermal mask to make it into a woollen balaclava that does not hide your thermal signature

Police versions of the Basic helmet (both with and without a neck protector)
A covered variant of the Basic Helmet

Now, if we were talking about completely new assets:

Bushmaster ACR (Rifle and GL variants)
G36C (Rifle, GL and AR variants)
SVD (both woodstock and metalstock) and SVD-12 (potentially using the RPK-12 except changing the Stock to the normal AK-12 Stock and giving it a 12 round magazine)
M4 (Rifle and GL variants)
Steyr A3 (Rifle and GL variants)

Versions of the Contact Gas Masks that maybe use some underlying mask to cover the head more
The Russian Armed Forces 6B47, both uncovered and covered variants
A Version of the Granit suit with its Hood up, and versions of both hood up and hood down with some Knee and Elbow Pads