It really depends on what you're looking for and your ability to spend money or not.
If you're on a budget, the Harley Benton dirt cheap strings are really good and they come in stainless steel, nickel, round wound, flat wound and with different gauges, so all you need is to pick up the ones you like.
If you're looking for THAT Motown sound in tune up to the last fret, but don't want to wait 2 decades for the tone to settle in, buy the DR Strings Legend flat wounds.
Or if you prefer a lighter gauge with more mids, try the Thomastik Infeld JF (Jazz Flat...wound).
If you want an even more lighter gauge with even more low mids, but not too much bass and more treble, try the ultra expensive Dogal Perfect Pitch Hellborg Flat Wound.
For the round wounds, if you're looking for a flat response, try the La Bella Super Steps.
If you like a dead precise in tune tone all along the fretboard, with a very light gauge, try the very expensive Dogal Perfect Pitch Hellborg Round Wound.
Or simply buy the Ernie Ball Slinky series for your bass as they are simply regular good string and quite cheap.
It's all about taste and use.