There are no sharps that are diatonic to the key of B flat. It is a flat key, with two flats (Bb and Eb) and the notes are: Bb, C, D, Eb, F, G, A, Bb.
If there are sharps being used, then they would be chromatic alterations. The most frequently used of those would be the C# (as a #9 - like in the "Hendrix chord") and the F# (as a #5, which is also related through the relative harmonic minor).
Two flats, B flat and E flat
There are two flats, B flat and E flat. It is the relative minor for B flat Major.
There are two flats in the key of B flat major: B flat and E flat.
The key of A flat major has four flats: B flat, E flat, A flat and D flat.
2 flats B-flat and E-flat
2 flats B-flat and E-flat
The key of A-flat major contains four flats: B, E, A, and D.
The key of B flat major, or g G minor, has two flats. The flats are B flat and E flat.
There are no flats in b-minor. B major has two flats, both B-flat and A-flat, but b-flat minor is the relative minor of D-major, which has a sharp key signature. The sharps in b-minor are F-sharp and C-sharp.
D flat major, or b flat minor. The flats are B, E, A, D and G, in that order.
5 b flat, e flat, a flat, d flat, and g flat
2. Eb and Bb