As for MP missions, I have had a lot of two / three player LAN games with my brother and friends and there are a few cooperative maps we always played. We didn't really enjoy the DM maps etc. Anyway, most of the maps came with OFP or Resistance.
- Everon - Oil war (?): Can't remember the name, first you have to ambush a convoy - later attack an enemy base. Designed for 7, playable with two or three and we played it a lot.
- Everon - 2-5 Coop: Rescue the captive in Entre Deux, then clear a farm. A lot of tactics were unleashed here, a lot went wrong, we had a great time. Especially the satchel-to-tank-sneak-at-the-farm.
- Nogova - 1-16 Cooperative: Petrovice has to be liberated. As the map is designed for a large amount of players, we always had to improvise to be able to actually win. There was a specific hill to the southeast (if I remember correctly) of Petrovice we occupied, with two Hummers full of ammo and weapons - the hill mined and satcheled. Damn, we only completed it once but it was fun.
- Not official - some map (Desert Rumble?) on Desert Island: each side had a base with planes, tanks and choppers. We used this map to do some A10 vs A10, M1A1 vs M1A1 and Hind vs A10 etc etc battles. Fun for a while. Don't remember the name though, sorry.
- Not official - selfmade defend against three enormous waves of east soldiers: Well, the 'title' says it all. In the center of Desert Island we made a base consisting of sandbags and bunkers - limited ammo / weapons before each play we decided what our weapons would be (Uzi, pistol or whatever we found fun).
- Nogova - War Cry: A map where you had to clear a town and villa of enemy forces. Fun for a few times.
- Malden - Desert Ambush: Ambush a Russian convoy. To be honest, we only completed this map twice and played it very often. I guess we never found the right tactic to survive or were with too few players but it was fun.
- Malden - Lost Squad: Chapoi (?) is isolated and has to be defended. Challenging, we never managed to hold Chapoi but completed the mission a few times by doing the unorthodox - retreat ASAP.
- Everon - Return to Eden: I played this with my brother, friends, cousin well numerous people and we all liked it.
You probably tried 1-9 Conquerors, we did it sometimes when tired of infantry combat (rarely) and 1-4 Shadowkiller.
I might have some maps for you in my MPMissionsCache, MP missions folder from my online play maybe a few for LAN play. Looking at it I think that a long long time ago we enjoyed Desperate Measures - where you have to hold a peninsula or something. Quite challenging considering that you have to depend on the skills of the A10 pilot. Pretty playable with two players.
EDIT: sorry if this got a bit long and is not useful, got carried away by the nice OFP memories...