Aside from books and Aebersolds, or rather, in addition to:
You might want to try to transcribe some basslines (or parts of them) yourself as well. That can be challenging at first, but it has the IMO great advantage of dealing with lines that are already in a full musical context. That does not necessarily make the lines "better", but I always figure, if they were good enough for the respective bandleader...
A great place to start could be the multi-CD-box "steamin'/cookin'/workin'/relaxin' with the Miles Davis Quintet" (am I forgetting one?). Paul Chambers. The bass is surprisingly audible (given the production date), it's a great bag of tunes to know, and while you can't dial out the bass, playing along with PC doesn't hurt. Another one of way too many excellent calls could be "My Funny Valentine/Four and more", by a later incarnation of the Miles Davis Quintet (Ron Carter, Tony Williams, George Coleman, Herbie Hancock). Great great lines.
Best
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