Personally, I have a dream list of some nice military rifles of the era:
I know we already have the full Army version, but I'd love the 1873 trapdoor Springfield carbine.
If Online ever jumps to the Epilogue, in 1907, then we can get the 1903 Springfield and the 1906 Type 38 Arisaka.
I also would like some revolvers:
A personal favorite, the 1895 Nagant Revolver; this one can be silenced because the ammo cylinder moves forward when the trigger is pulled, making it flush with the barrel and trapping the gases that normally escape.