There are no rules for tuning a bass guitar other than the one already alluded to: pay attention to the tension keeping the individual string tension and total neck tension reasonable. The tension charts from Circle K Strings
and D'Addario Strings
will let you do that with any tuning.
If you want to play songs that are written in a drop tuning then you either have to drop tune or you play the low note up an octave but that may force you to use an awkward fingering that won't permit you to play as fast as you like. You can get clip on headstock tuners (like the Snark) or tuning pedals that will allow you to drop tune when needed pretty quickly. Or you can use a Hipshot drop tuning key on your E string. Just flip a lever to go from standard to drop tuning. All kinds of tunings are in use on TB. There are many variations of the standard fourths tuning and drop tunings using a variety of starting notes for the low string. There are even a few of us who tune in fifths. So try any tuning that strikes your fancy. Just keep in mind that if you need to tune a string up by more than a whole step you probably want to consult a tension chart and choose a special gauge string for that.