Back to the blues scale, I found out other two examples to go outside.
1) The first is an example from a Bb blues played by Greg Osby. As far as I my ear goes, he plays mainly in Bb altered chord, that is on the harmony of B natural melodic minor . He goes on with these notes: Bb, Bnatural, Db, Dnatural, E, Gflat, Ab, Bb
I may be wrong of course, I've no good hear. You may hear him in this video, starting from 50:11, the three saxophonists play Sonny Rollins' blues, Tenor Madness, then Greg Osby plays the first impro.
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