There are a great deal of Soviet prototype and experimental small arms that could be considered.
1.Mosin M91 modified by Fedorov and Degtyarev in 1924, fed from detachable magazine
2.Mosin M91 modified by Tokarev with swinging bayonet
3.Tokarev 1908 self-loading conversion of Mosin M91
4.Tokarev 1912 self-loading conversion of Mosin M91
5.FN Brauning self-loading conversion of Mosin M91 with box magazine
6.FN Brauning self-loading conversion of Mosin M91 with rotary magazine
7.Yasnikov self-loading conversion of Mannlicher M95
8.Fedorov-Degtyarev light machine gun, caliber 6.5mm
9.Fedorov-Degtyarev 1924 light machine gun, caliber 7.62mm
10.Konovalov SVK 1925
11.Fedorov 1926 self-loading rifles, caliber 7.62mm
12.Simonov 1927 light machine gun
13.Kolesnikov 1927 light machine gun
14.Tokarev 1928 self-loading carbine, caliber .351 WSL
15.“KoKo” No.2 self-loading rifle designed by Degtyarev, Kuznetsov, and Bezrukov
16.Moshchevitin self-loading rifle
17.Maxim-Tokarev 1927 machine gun
18.Kedar self-loading rifle
19.Tokarev SVT 1930
20.Tokarev No.1 full-auto pistol-carbine
21.Popov water-cooled AVP 1930
22.Popov AVP 1931
23.Simonov AVS 1930
24.Simonov AVS 1931
25.Degtyarev AVD 1932
26.Degtyarev-Lewis light machine gun, fed from flexible strips
27.Prilutsky submachine gun
28.Kolesnikov submachine gun
29.Korovin 1930 submachine gun
30.Avtomat Korovin 1933, caliber .351 WSL
31.ONK 1933 self-loading sniper rifle
32.Korovin 1934 submachine gun
33.Tokarev AKT 1934
34.Mamontov SVM 1936
35.Goryainov SVG 1936
36.Degtyarev PPD 1937
37-38.Rukavishnikov-Bulkin 1938 self-loading rifle
Rukavishnikov SVR 1938
39-40.BNK-4 self-loading rifle
BNK-6 self-loading rifle
41.Soviet copy of Czech Holek self-loading rifle, with scope, developed by the engineers of TsKB-2
42.Korovin TsKB SV-6 light machine gun
43.Korovin TKB-135 light machine gun
44.Degtyarev DP-39, fed from metalic belt
45.Degtyarev KB-P-260
46.Goryunov GVG 1941 machine gun, fed from Maxim canvas belt
47.Maine pistol caliber carbine
48.Slostin KB-P-85 pistol caliber carbine
49.Korovin 1942 submachine gun
50.Shpitalniy 1943 submachine gun
51.Shpitalniy 1943 pistol caliber light machine gun (belt-fed submachine gun)
52.Tula TKB-340 pistol caliber light machine gun (belt-fed submachine gun)
53.Silin TKB-264-42 belt-fed light machine gun
54.Bulkin TKB-335 1st model light machine gun
55.KB-P-290 self-loading carbine, caliber 7.62mm M43
56.KB-P-330 self-loading carbine, caliber 7.62mm M43
57.Rukavishnikov SKR 1944, caliber 7.62mm M43
58.Simonin SKS 1944, caliber 7.62mm M43
59.Savin SKS 1944, caliber 7.62mm M43
60.Korobov SKK 1944, caliber 7.62mm M43
61.Petrov SKP 1944, caliber 7.62mm M43
62.Simonov AKS-M-P-44, caliber 7.62mm M43
63.Bulkin TKB-392, caliber 7.62mm M43
64.Avtomat KB-P-315 No.1
65.Avtomat KB-P-280 No.2
66.Avtomat Simonov RPS-MZ-P-44
67.Avtomat Kuzmishchev 1944
68.Avtomat KB-2KB-P-280 No.4
69.Avtomat Shpagin No.4
70.Avtomat Tokarev 1944
71.Avtomat Korovin 1944 No.1
72.Avtomat Korovin 1944 No.2
73.Avtomat Bulkin 1944
74.1942 Vasiliev’s full auto device for Mosin Nagant, caliber 7.62mm Tokarev