Here’s a drill we use almost every practice. This drill accomplishes several objectives: Conditioning, Speed dribbling, and lay-ups at full speed under “game-like” pressure, and defense. The second drill, 3 on 3 Cutthroat is a great way to teach the transition game.

Chase Drill
Player One stands at the three point arc, foul line extended.
Player Two has the ball at the baseline and lobs a pass slightly over the head of Player One.
Player One sprints to the ball and speed dribbles the length on the court for a lay-up.
After throwing the lob pass, Player Two chases down Player One, trying to catch him and play defense to prevent the lay-up.

We do this from both ends of the court at the same time (so there are always two players dribbling and two players chasing).  We start with right handed lay-ups and then switch to left handed lay-ups.

3 on 3 Cutthroat
This is a full court drill with a lot of running.

3 players on offense start at one end and attack the basket at the other end while the other 3 play defense from the half court on.

If the offense scores they keep the ball and head to the other basket. the team that did not get the ball play defense to the half court while a new 3 come on and defend the other basket.

If the defense gets the ball with a turnover or rebound they are now on offense and who was on offense plays defense to the half court as a new 3 comes on to defend the other basket.

This is a great way to teach the transition game while also getting some conditioning in at a same time.