When looking for volleyball drills to use in your training, or working to develop your own, one of the things you should pay attention to is the way the reps are structured. By that I mean who gets the most reps? Do the stronger players get more repetitions and the weaker players fewer? Or are the weaker players the ones getting more reps?
Your objectives for that training session, and by extension the drill, should dictate which way you want to go. For example, if you do match preparation then you probably want your starters getting more reps. At least they need more focused reps than your non-starters. Another example is focusing a serve receive passing drill on your OHs and Liberos. In that case your MBs get few, if any, reps.
A developmental situation reverses things. In that case, you probably want your weaker players getting more reps than the better ones. You want to avoid “punishment” oriented drills. Those are ones which take players out after they make an error (we could talk about other reasons to avoid these sorts of things, but that is a topic for another day).
An example of this is a serving game some coaches use. It is one in which a player missing a serve must go to the other side of the net until one of their teammates can hit them. This inherently sees the weaker servers serving the ball less frequently. A better way to go is the Amoeba game in which it’s the successful servers getting fewer contacts.
Another example of this is the get 2 serve receive drill. By keeping players in until they execute multiple good passes, you have your weaker players in there longer than your better ones.
Bottom line, be aware of how the play will be shared around in any given drill and make sure that fits with your objectives.