The B minor thirteenth chord is a 6-note chord consisting of the notes B, D, F#, A, C# and G#.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Bm13.
Interactive piano diagram for the B minor thirteenth chord
Chords that are a subset of Bm13. These contain less notes but all of them are included in Bm13.