Each bass will be different. My standard string I use are the DiAddario Pro Steels, as they sound great to my ears.
On my fretless Jazz I have an older flatwounds, Diddario Chromes, and after trying many others, that is what sounds best.
On an older P bass with Geezer pickups, I struggled to find the right string for that, but have ended up with Earnie Ball Cobalt Flats.
My Five string Spector like Pro Steels, but my Ibanez and LTD likes Rotosound 66s.
So those are a few I like.
The EB cobalt flats are very interesting, with a broken in RW sound. They really made a p bass come alive, where others didn’t. It very much a pleasing sound. They are worth a try sometime, and I’m a RW guy at heart.