Are you looking for "cheese*" strats or things that will make people rage?.
*Which in fact is not actually cheese in the proper sense (strats which are meant to take the opponent by surprise but are easy to defeat once scouted or prepared for).
SU:
Ghost sandbags, Clowncars (against OKW), double snipers (a. OH), maxim spam, Su76 spam into call ins, dshk spam, M4C, demos, flares/mines in doors, FHQ all in strats, Partisan maphack...
OH:
Double sniper, 222 spam, PW s. , PV s. , Osstruppen, Assault Gren s. just to lose with enough VP difference to gain faction choice

, Stug-e into Tiger, Command PIV, CAS, Strafe + Stuka dive bomb...
USF:
Rifle spam, Rifle zook/bar blob, RET zook blob, decrew to get more popcap, CalliOP, demo, M10 crush...
OKW:
Volk shreck blob, Stuka, JPIV phaseshifting, Command PV mark vehicle, PF-JLI s., Vet4 Obers, Ghost wire, Ghost sandbags, JT on certain maps, Falls to kill Katyushas, Sturmtiger, Kubel maphack, IR HT + suppression maphack...
UKF:
Double sniper, Emplacement spam, Cancer commander, demos, RE spam, RE piat blobs, Comet s., most UKF offmaps (arty cover, 1 shotting OKW buildings), Cromwell crush, firefly tulips shots...