it also depends on your budget ofcourse, if you are really plankton (like me for instance) you might want to try the lower bots like @drotto , @minnowhelper-1 (up to @minnowhelper-5 )and probably a lot more i havent found yet who will give you a very light boost for 0.001sbd only (starting at -). It's not much but there's also not much you can do with 1 promille sbd, but its enough to get you over dust treshold so your posts pay out even if you don't get traction (which is kinda hard at the start, not everyone can pump out a 100s dollars post a week and not everyone is a whale who came into it with money and can simply upvote themselves straight from here to mars like that)

if anyone knows of any others please let me know :)
there's also

@nanobot , @minibot , @microbot (but those have a max requirement for sp if you want to use them, different each)

these can get you enough to promote your next post and give you a very slight increase in sp too, which in the beginning is very linear and i think you need several thousand to actually start moving towards an exponential curve there, i didnt quite do the math

the minnowhelper series doesn't leave a comment either so your reply section looks nice and clean, thats all personnal preference