Mostly finger style using index and middle. How I first learned on DB in grade school orchestra.
Got an electric bass guitar in jr high started playing with index and ring, because the fingers were about the same length. Dropped DB, unfortunately [biggest regret of my life].
Forward to college, tried [unsuccessfully] picking up DB again and went back to index and middle. Sometimes use all three, but in a random way - not i-m-r, r-m-i, nor galloping - more like i-m-i-r - but more random. If playing with one finger, like pumping roots, usually use the ring finger.
Sometimes use floating thumb, sometimes anchor - depending where I'm picking for tone will anchor to the top of a pup, the pick guard, even the bridge. I mostly like plucking right behind the bridge pup between the bridge - lots of stiff attack. Or right in front of the bridge pup - a little more boomy and strings are a little looser. If I want to simulate a DB will anchor to side of neck and play over front of fretboard - does give the sound the woody slap and string "bloom".
Thumb, index, and middle for slap and pop.
Started using a pick. Alternate between all downstrokes, but use a lot of alternating up/down on fast songs and passages.