Yes, I see one-way BE fares to/from numerous EU cities. While these can't be combined with a PE fare on a single ticket, they can be booked as one-way tickets. Doesn't sound like OP is actually doing one-way searches (or maybe trip is outside the EU?). These one-way BE fares tend to cost somewhat more than the roundtrip BE fares (on an each-way basis), but they can certainly be booked on delta.com with a one-way search. YQ on following fares is $200 each way.