my favorite resources are
1. Lil Rev's book, 101 ukulele licks. I don't have access to my copy right now, but I remember that it had blues licks for every key. Of course, with a little bit of theory you can transpose any or all of those licks into whatever key you want.
2. I have followed for years Tenthumbspro. He has two emphases. One is very rock/pop oriented. The other is devoted to blues and music composition. He'll devote lessons to the pentatonics in various keys, to making your own solos, or to riffs in the style of this-or-that person.