I get a lot of mileage out of the major scale, mixolydian (which is just the major scale with a flatted 7th), minor pentatonic, and Dorian (which is just a minor pentatonic with the 2 and 6 added in).
But really most of my thoughts, and I feel the most important ones, are about how things feel, and trying to make things feel groovy through rhythmic concepts. That's how you slay it with R-5-8, it's not the notes per se but where you put them in the flow.
Note density and simplicity vs complexity are big considerations for me; sometimes no fill is the best fill, right? So either matching the drummer or soloist, or contrasting from them, in terms of the density and overall melodic shape of our lines. It's definitely conversational and based on how the groove feels to me.
I often think terms of "staying home" or "heading out". Some drummers stay home a lot, I might head out more often with them. Some drummers head out every chance they get, I'll stay home a lot more with them. Some soloists and singers seem to prefer a stable platform; I'll stay home with them most of the time. Some seem to thrive on the energy when I head out with them to places unknown, I'll do my best to stoke the fires of adventure for them.
The main thing I like is variety. I don't want to play the same feels and stuff over and over. I like to mix things up from tune to tune, and to a lesser extent within the same tune. It's part of why I am serious about soloing. I personally find it boring to listen to the same person take solo after solo all night long, no matter how good they are. Give the drummer some! Let the bass player cut one! Variety is the spice of life. Solos don't have to be complex, they just have to feel good, and if they're melodic that's a huge win.