Bubbles have long been a go-to speech and language therapy tool. They're great, I am not suggesting you stop using them to target /b/ and /p/ sounds, "wet," etc.
But, if you run out of bubbles, or want to try something new to engage kids in a joint attention activity, BubblesAR (free) is simple and cool. Tap the circle to blow a bubble in your "room" (the camera is activated). Tap longer and the bubble will be bigger. Whatever the circle is positioned over will be "reflected" in the bubble as it floats, giving you the opportunity to have the child name items in the room. Tap the bubble to "pop" it for a cool confetti effect. That's it!