In terms of standard actions, the most common are Attack and Cast a Spell, but it’s also possible to Dash, Dodge, Disengage from a fight, Hide, Use an Object, Help an ally, Stabilize a fallen ally, or Activate a Magic Item. Bonus actions are usually class-specific abilities or particular spells, which can also be done in a turn if available. Lastly, free actions – minor things like drawing a weapon or communicating – can be done. Outside of your own turn, you can often take reactions to specific triggers.