A telescope and at least two (one high-power and one low-power) eyepieces are enough to get you started in amateur astronomy. You can enhance and expand your observations further using accessories. There are plenty of telescope accessories to choose from including Barlow lenses, star diagonal and a camera adapter among others. The accessories you’ll find most useful are telescope filters.
A telescope filter will not increase the magnification or field of view of your telescope. But, it can make it easier to observe or photograph different celestial objects by filtering out and letting in certain light wavelengths.
Depending on the filter you are using, this can reduce glare when observing the moon and bright stars or keep out light pollution from streetlights.
Before you spend a lot of money buying additional eyepieces and other accessories, consider buying at least two telescope filters. It’ll make a big improvement in your viewing experience.