Certainly, here are three sentences for each part of the sentence pattern "there is," "there is a," and "there are":

There is a beautiful sunset over the ocean.

There is a new book on the shelf waiting to be read.

There is a delicious aroma coming from the kitchen.

There is an old oak tree in the middle of the park.

There is a problem with the computer's operating system.

There is a gentle breeze on this sunny day.

There are many students in the classroom, eager to learn.

There are numerous stars in the night sky.

There are several interesting museums to visit in the city.