Depends on size at introduction and sie of tank. I wouldn't hesitate to put angels in with oscars if the parrameters were right. Angels are a medium to large fish that looks bigger than it is. Oscars are not fin nippers, and will leave most fish alone unless they are crowded. To me it would be a different but interesting combo, but you would want a very large tank for this idea Probably a 6 footer if you plan to do more than one of each.
Otherwise, there are a lot of fish compatable with angels, including the above mentioned tetra's. Just avoid fin nippers and the smallest breeds (neons in particular) and you'll be fine.
I would say yes that angels and oscars will go together. You will have to put the angels in first and get them to a good size ( I say them because they will do better in a school )then you can put in an oscar(One oscar , if you wanted to put in more that means bigger tank), but it should about an 1-,1 1/2 inches. Dont feed the oscar live foods that only makes them more agressive. And as Daveedka says you will need a big tank, 6 foot would minimun, i would say 8 feet to give them space to run if they (angels)get bullied.
Oscars are not as a rule an aggressive fish. they can be if crowded as mentioned, and if you have a pair they can get real ugly when spawning but otherwise they are generally docile. Angelfish are likewise a cichlid and can exibit similar behavior in the wrong conditions. Oscars are a predator, but that does not make them a mean or aggressive fish in general.
I have seen angels kept with oscars in a large setup with no problems.Like daveedka said oscars are not really that aggresive and its just their sheer size that makes them to be lumped with the more aggressive cichlids.If the O does not think it can swallow the fish and they are not crowded for territory then they will do just fine.
If these monster tanks that others are suggesting are out of your range (they are sure out of mine....for now ) I have kept a pair of apistogramma with angels in what most would consider a pretty small tank (29g) with no problems after the initial period of acclimation. The apistos did not breed, which certainly would have changed the equation, but for display purposes the mix worked fine. Just to be safe, I think it is best to have a hospital/Q/breeding tank ready any time you are mixing cichlids, as conflicts can get ugly fast.
I find that oscars are very placid cichlids and like Daveedka said if they are not crowded they will do fine. I find this with all cichlids . I have mainly cichlids in my 1850g with 40 plus cichlids some very small(3 inch firemouth) some big(16 inch dovii) and I never have any fights anymore , everyone has found their place(I also have 4 oscars in this tank). I also believe it has a lot to do with what you feed them, if you feed live fish it makes them much more aggresive.