This is not a comprehensive list, but as far as I know the following list probably accounts for ~90% of games and is pretty much the RUSSIA PLAYBOOK as I understand it:
build all infantry (optional: bid soviet infantry), march everything to Moscow, fly in Allied fighters, die slow. Hope the allies can save the day elsewhere.
same as #1 but send some units to Iraq or (not ‘and’) Finland to try and increase income.
build inf and mech R1 (optional: bid soviet infantry), buy time at Belarus, march far east troops home, fly in Allied fighters, check your battle calculator and buy artillery when its time, counterattack
build tanks R1 (optional: bid artillery on Eastern front), threaten counterattack to delay Barbarossa, take no sh!t from Italy, march far east troops home, counterattack opportunistically
build 3 mechs R1 and send planes to Yunnan (optional: bid fighters in moscow and stalingrad, and/or inf in yunnan and artillery in suiyuyan, shensi, szechwan, kweichow); far east troops go to Buryatia then Amur then Manchuria (optional: bid artillery out east), die, but watch Allies kill Germany
Gargantua, Cow, and others have discussed these in the past
This is actually a really good post; with a pretty complete breakdown of viable options. Those are the primary concepts.